Online Etymology Dictionary

sy-: form of syn- before -s- or -z-.
sybarite (n.): "person devoted to pleasure," 1590s, literally "inhabitant of Sybaris," ancient Greek town in southern Italy, whose people were noted for their love of luxury. From Latin Sybarita, from Greek Sybarites.
sybaritic (adj.): 1610s, from Latin sybariticus, from Greek sybaritikos, from Sybarites (see sybarite).
sycamore (n.): mid-14c., sicamour "mulberry-leaved fig tree," from Old French sicamor, sagremore, from Latin sycomorus, from Greek sykomoros "African fig-tree," literally "fig-mulberry," from sykon "fig" (see fig) + moron (see mulberry). But according to many sources this is more likely a folk-etymology of Hebrew shiqmah "mulberry."

A Biblical word, originally used for a wide-spreading shade tree with fig-like fruit (Ficus sycomorus) common in Egypt, Palestine, Syria, etc., whose leaves somewhat resemble those of the mulberry; applied in English from 1580s to a large species of European maple (also plane-tree), perhaps because both it and the Biblical tree were notable for their shadiness (the Holy Family took refuge under a sycamore on the flight to Egypt), and from 1814 to the North American shade tree that also is called a buttonwood, which was introduced to Europe from Virginia 1637 by Filius Tradescant).

Spelling apparently influenced by sycamine "black mulberry tree," which is from Greek sykcaminos, which also is mentioned in the Bible (Luke xvii:6). For the sake of clarity, some writers have used the more Hellenic sycomore in reference to the Biblical tree.
sycophancy (n.): 1620s, from sycophant + -cy, or else from Latin sycophantia, from Greek sykophantia "false accusation, slander; conduct of a sycophant," from sykophantes.
sycophant (n.): 1530s (in Latin form sycophanta), "informer, talebearer, slanderer," from Middle French sycophante and directly from Latin sycophanta, from Greek sykophantes "false accuser, slanderer," literally "one who shows the fig," from sykon "fig" (see fig) + phainein "to show" (see phantasm). "Showing the fig" was a vulgar gesture made by sticking the thumb between two fingers, a display which vaguely resembles a fig, itself symbolic of a vagina (sykon also meant "vulva"). The modern accepted explanation is that prominent politicians in ancient Greece held aloof from such inflammatory gestures, but privately urged their followers to taunt their opponents. The sense of "mean, servile flatterer" is first recorded in English 1570s.
The explanation, long current, that it orig. meant an informer against the unlawful exportation of figs cannot be substantiated. [OED]
sycophantic (adj.): 1670s, from Greek sykophantikos, from sykophantes (see sycophant). Related: Sycophantical (1560s).
Sydney: Australian city, founded 1788 and named for British Home Secretary Thomas Townshend, 1st Viscount Sydney (1733-1800). The family name (also Sidney) is literally "dweller by the well-watered land," from Old English sid "side" + ieg "island."
syl-: assimilated form of Greek syn- before -l-.
syllabic (adj.): 1728, from Modern Latin syllabicus, from Greek syllabikos "of or pertaining to a syllable," from syllabe "a syllable" (see syllable). Related: Syllabical (1520s).
syllable (n.): late 14c., from Anglo-French sillable, alteration of Old French silabe "syllable" (12c., Modern French syllabe), from Latin syllaba, from Greek syllabe "that which is held together; a syllable, several sounds or letters taken together," i.e. "a taking together" of letters; from syllambanein "take or put together, collect, gather," from assimilated form of syn- "together" (see syn-) + stem of lambanein "to take" (see analemma). The unetymological -le apparently is by analogy with participle and principle.
syllabus (n.): 1650s, "table of contents of a series of lectures, etc.," from Late Latin syllabus "list," ultimately a misreading of Greek sittybos "parchment label, table of contents," of unknown origin. The misprint appeared in a 15c. edition of Cicero's "Ad Atticum" (see OED). Had it been a real word, the proper plural would be syllabi.
syllepsis (n.): use of a word at once in both a literal and metaphoric sense, 1570s, from Late Latin syllepsis, from assimilated form of Greek syn "together" (see syn-) + lepsis "a taking," related to lambanein (see analemma). Related: Sylleptic.
syllogism (n.): late 14c., from Old French silogisme "a syllogism, scholastic argument based on a formula or proof" (13c., Modern French syllogisme), from Latin syllogismus, from Greek syllogismos "a syllogism," originally "inference, conclusion; computation, calculation," from syllogizesthai "bring together before the mind, compute, conclude," literally "think together," from assimilated form of syn- "together" (see syn-) + logizesthai "to reason, count," from logos "a reckoning, reason" (see logos).
syllogistic (adj.): 1660s, from Latin syllogisticus or directly from Greek syllogistikos, from syllogizesthai (see syllogism).
sylph (n.): 1650s, "air-spirit," from Modern Latin sylphes (plural), coined 16c. by Paracelsus (1493-1541), originally referring to any race of spirits inhabiting the air, described as being mortal but lacking a soul. Paracelsus' word seems to be an arbitrary coinage, but perhaps it holds a suggestion of Latin silva and Greek nymph, or Greek silphe "a kind of beetle," but French etymologists propose a Gaulish origin. The Century Dictionary comments that, "to occultists and quacks like Paracelsus words spelled with -y- look more Greek and convincing." The meaning "graceful girl" first recorded 1838, on the notion of "slender figure and light, airy movement" [OED].
sylphid (n.): younger or smaller variety of sylph, 1670s, from French sylphide (1670s), from sylphe (see sylph) + diminutive suffix.
sylvan (adj.): "of the woods," 1570s, from Middle French sylvain (1530s), from Latin silvanus "pertaining to wood or forest" (originally only in silvanae "goddesses of the woods"), from silva "wood, woodland, forest, orchard, grove," of unknown origin. The unetymological -y- is a misspelling in Latin from influence of Greek hyle "forest," from which the Latin word formerly was supposed to derive.
Sylvanus: Roman deity, from Latin Silvanus, used by the Romans as the proper name of a god of woods and fields, identified with Pan, noun use of adjective, literally "pertaining to woods or forest" (see sylvan).
Sylvester: masc. proper name, from Latin silvestris, literally "of a wood, of a forest, woody, rural, pastoral," from silva "wood, forest" (see sylvan). St. Sylvester's Day is Dec. 31.
Sylvia: fem. proper name, literally "inhabiting woods," from Latin silva "wood, forest" (see sylvan). Also the genus name of warblers, hence adjective Sylvian.
sym-: assimilated form of syn-, from Greek form of syn- in compounds with words beginning in -b-, -m-, -p-, -ph-, -ps-.
Symbionese (adj.): in Symbionese Liberation Army (SLA), name adopted by a socialist revolutionary group active in U.S. 1972-76, coined from simbion "an organism living in symbiosis, from symbioun (see symbiosis) + people-name ending -ese.
symbiosis (n.): 1876, as a biological term, "union for life of two different organisms based on mutually benefit," from Greek symbiosis "a living together," from symbioun "live together," from symbios "(one) living together (with another), partner, companion, husband or wife," from assimilated form of syn- "together" (see syn-) + bios "life" (see bio-). Given a wider (non-biological) sense by 1921. An earlier sense of "communal or social life" is found in 1620s. A back-formed verb symbiose is recorded from 1960.
symbiotic (adj.): 1882, in biology, from stem of symbiosis + -ic. Of human activities from 1951. Related: Symbiotical; symbiotically.
symbol (n.): early 15c., "creed, summary, religious belief," from Late Latin symbolum "creed, token, mark," from Greek symbolon "token, watchword, sign by which one infers; ticket, a permit, licence" (the word was applied c.250 by Cyprian of Carthage to the Apostles' Creed, on the notion of the "mark" that distinguishes Christians from pagans), literally "that which is thrown or cast together," from assimilated form of syn- "together" (see syn-) + bole "a throwing, a casting, the stroke of a missile, bolt, beam," from bol-, nominative stem of ballein "to throw" (see ballistics).

The sense evolution in Greek is from "throwing things together" to "contrasting" to "comparing" to "token used in comparisons to determine if something is genuine." Hence, "outward sign" of something. The meaning "something which stands for something else" first recorded 1590 (in "Faerie Queene"). As a written character, 1610s.
symbolic (adj.): 1650s, from symbol + -ic, or from Greek symbolikos. Related: Symbolical (c. 1600); symbolically.
symbolise (v.): chiefly British English spelling of symbolize. For suffix, see -ize. Related: Symbolised; symbolising; symbolisation.
symbolism (n.): 1650s, "practice of representing things with symbols," from symbol + -ism. Applied to the arts by 1866; attested from 1892 as a movement in French literature, from French symbolisme (see symbolist).
symbolist (n.): 1580s, from symbol + -ist. From 1888 in reference to a literary movement that aimed at representing ideas and emotions by indirect suggestion rather than direct expression, from French symboliste, coined 1885 by poet Paul Verlaine (1844-1896). Rejecting realism and naturalism, they attached symbolic meaning to certain objects, words, etc.
symbolization (n.): c. 1600, from French symbolisation, from symboliser (see symbolize).
symbolize (v.): c. 1600, "represent by a symbol," also "be a symbol of," from French symboliser, from symbole (see symbol). Related: Symbolized; symbolizes; symbolizing.
symbology (n.): 1840, contracted from symbolology, from comb. form of Greek symbolon "token" (see symbol) + -ology.
symbololatry (n.): "worship of symbols," 1828, from symbolo-, comb. form of symbol, + -latry.
symmetric (adj.): 1796, from symmetry + -ic. Earlier in the same sense was symmetral (1650s).
symmetrical (adj.): 1751, from symmetry + -ical. Related: Symmetrically (1570s).
symmetrize (v.): 1749, from French symmétriser, from symmétrie (see symmetry). Related: Symmetrize; symmetrizing.
symmetrophobia (n.): 1809, from comb. form of symmetry + -phobia. Supposed to be evident in Egyptian temples and Japanese art.
symmetry (n.): 1560s, "relation of parts, proportion," from Middle French symmétrie (16c.) and directly from Latin symmetria, from Greek symmetria "agreement in dimensions, due proportion, arrangement," from symmetros "having a common measure, even, proportionate," from assimilated form of syn- "together" (see syn-) + metron "meter" (see meter (n.2)). Meaning "harmonic arrangement of parts" first recorded 1590s.
sympathetic (adj.): 1640s, "pertaining to sympathy," from Modern Latin sympatheticus, from late Greek sympathetikos "having sympathy," from sympathein, from sympathes "having a fellow feeling, affected by like feelings" (see sympathy). In English, the meaning "having fellow feeling, susceptible to altruistic feelings" is recorded from 1718.

In the anatomical sense, "subject to a common nervous influence," the word is attested from 1769, from Modern Latin (nervus) sympathicus, coined by Jacques-Benigne Winslow (1669-1760), Danish anatomist living in Paris. Related: Sympathetical (1630s); Sympathetically (1620s).
sympathise (v.): chiefly British English spelling of sympathize (q.v.); for suffix, see -ize. Related: Sympathised; sympathising.
sympathize (v.): "have fellow-feeling," c. 1600, from Middle French sympathiser, from sympathie (see sympathy). Earlier in a physiological sense (1590s). As "express sympathy," from 1748. Related: Sympathized; sympathizing.
sympathizer (n.): 1815, agent noun from sympathize.
sympathy (n.): 1570s, "affinity between certain things," from Middle French sympathie (16c.) and directly from Late Latin sympathia "community of feeling, sympathy," from Greek sympatheia "fellow-feeling, community of feeling," from sympathes "having a fellow feeling, affected by like feelings," from assimilated form of syn- "together" (see syn-) + pathos "feeling" (see pathos).

In English, almost a magical notion at first; used in reference to medicines that heal wounds when applied to a cloth stained with blood from the wound. Meaning "conformity of feelings" is from 1590s; sense of "fellow feeling, compassion" is first attested c. 1600. An Old English loan-translation of sympathy was efensargung.
sympatric (adj.): 1904, from assimilated form of syn- + Greek patra "fatherland," from pater "father" (see father (n.)) + -ic. Opposite of allopatric.
symphonic (adj.): 1854 "involving similarity of sounds or harmony" (implied in symphonically); see symphony + -ic. Meaning "pertaining to a symphony" is from 1864. Earlier was symphonious (1650s).
symphony (n.): c. 1300, a name given to various types of musical instruments, from Old French simphonie, sifonie, simfone "musical harmony; stringed instrument" (12c., Modern French symphonie) and directly from Latin symphonia "a unison of sounds, harmony," from Greek symphonia "harmony, concord of sounds," from symphonos "harmonious, agreeing in sound," from assimilated form of syn- "together" (see syn-) + phone "voice, sound," from PIE root *bha- (2) "to speak, tell, say" (see fame (n.)).

Meaning "harmony of sounds" in English is attested from late 14c.; sense of "music in parts" is from 1590s. "It was only after the advent of Haydn that this word began to mean a sonata for full orchestra. Before that time it meant a prelude, postlude, or interlude, or any short instrumental work." ["Elson's Music Dictionary"] Meaning "elaborate orchestral composition" first attested 1789. Elliptical for "symphony orchestra" from 1926. Diminutive symphonette is recorded from 1947.
symphysis (n.): union of bones, 1570s, medical Latin, from Greek symphysis "a growing together, union," from assimilated form of assimilated form of syn "together" (see syn-) + physis "growth" (see physics). Related: Symphytic.
symposium (n.): 1580s, "account of a gathering or party," from Latin symposium "drinking party, symposium," from Greek symposion "drinking party, convivial gathering of the educated" (related to sympotes "drinking companion"), from assimilated form of syn- "together" (see syn-) + posis "a drinking," from a stem of Aeolic ponen "to drink," cognate with Latin potare "to drink" (see potion).
The symposium usually followed a dinner, for the Greeks did not drink at meals. Its enjoyment was heightened by intellectual or agreeable conversation, by the introduction of music or dancers, and by other amusements. [Century Dictionary]
The sense of "a meeting on some subject" is from 1784. Reflecting the Greek fondness for mixing wine and intellectual discussion, the modern sense is especially from the word being used as a title for one of Plato's dialogues. Greek plural is symposia, and the leader of one is a symposiarch (c. 1600 in English). Related: Symposiac (adj.); symposial.
symptom (n.): 1540s, re-Latinized from sinthoma (late 14c.), from Medieval Latin sinthoma "symptom of a disease," altered from Late Latin symptoma, from Greek symptoma "a happening, accident, disease," from stem of sympiptein "to befall, happen; coincide, fall together," from assimilated form of syn- "together" (see syn-) + piptein "to fall," from PIE *pi-pt-, reduplicated form of root *pet- "to rush; to fly" (see petition (n.)).

Spelling restored in early Modern English in part by influence of Middle French symptome (16c.). General (non-medical) use is from 1610s.