Online Etymology Dictionary

Sens: city in north-central France, Roman Senones, the capital of the Gaulish people of the same name.
sensate (adj.): c. 1500, from Late Latin sensatus "gifted with sense," from sensus "perception, feeling, undertaking, meaning" (see sense (n.)). From 1937 in sociology. As a verb from 1650s.
sensation (n.): 1610s, "a reaction to external stimulation of the sense organs," from French sensation (14c.) and directly from Medieval Latin sensationem (nominative sensatio), from Late Latin sensatus "endowed with sense, sensible," from Latin sensus "feeling" (see sense (n.)). Meaning "state of shock, surprise, in a community" first recorded 1779.
The great object of life is sensation -- to feel that we exist, even though in pain. It is this 'craving void' which drives us to gaming -- to battle, to travel -- to intemperate, but keenly felt, pursuits of any description, whose principal attraction is the agitation inseparable from their accomplishment. [Lord Byron, letter, Sept. 6, 1813]
sensational (adj.): "of or pertaining to sensation or the senses," 1840; "aiming at violently excited effects," 1863, from sensation in its secondary sense. Related: Sensationalistic; sensationalistically.
sensationalism (n.): 1846 in philosophy, "theory that sensation is the only source of knowledge;" 1865, of journalism that aims to excite the feelings, from sensational + -ism.
sensationalist: 1846 in philosophy; 1868 of writers; from sensational + -ist. Related: Sensationalistic.
sensationalize (v.): 1863, from sensational + -ize. Originally of audiences as well as topics. Related: Sensationalized; sensationalizing.
sense (n.): c. 1400, "faculty of perception," also "meaning, import, interpretation" (especially of Holy Scripture), from Old French sens "one of the five senses; meaning; wit, understanding" (12c.) and directly from Latin sensus "perception, feeling, undertaking, meaning," from sentire "perceive, feel, know," probably a figurative use of a literally meaning "to find one's way," or "to go mentally," from PIE root *sent- "to go" (source also of Old High German sinnan "to go, travel, strive after, have in mind, perceive," German Sinn "sense, mind," Old English sið "way, journey," Old Irish set, Welsh hynt "way"). Application to any one of the external or outward senses (touch, sight, hearing, etc.) in English first recorded 1520s.
A certain negro tribe has a special word for "see;" but only one general word for "hear," "touch," "smell," and "taste." It matters little through which sense I realize that in the dark I have blundered into a pig-sty. In French "sentir" means to smell, to touch, and to feel, all together. [Erich M. von Hornbostel, "Die Einheit der Sinne" ("The Unity of the Senses"), 1927]
Meaning "that which is wise" is from c. 1600. Meaning "capacity for perception and appreciation" is from c. 1600 (as in sense of humor, attested by 1783, sense of shame, 1640s).
sense (v.): "to perceive by the senses," 1590s, from sense (n.). Meaning "be conscious inwardly of (one's state or condition) is from 1680s. Meaning "perceive (a fact or situation) not by direct perception" is from 1872. Related: Sensed; sensing.
senseless (adj.): 1550s, "without sensation," from sense (n.) + -less. Of actions, etc., "devoid of purpose, proceeding from lack of intelligence," it is attested from 1570s. Related: Senselessly; senselessness.
senses (n.): "mental faculties, conscious cognitive powers, sanity," 1560s, from sense (n.). Meaning "faculties of physical sensation" is from 1590s.
sensibility (n.): late 14c., "capability of being perceived by the senses; ability to sense or perceive," from Old French sensibilite, from Late Latin sensibilitatem (nominative sensibilitas), from sensibilis (see sensible). Rarely recorded until the emergence of the meaning "emotional consciousness, capacity for higher feelings or refined emotion" (1751). Related: Sensibilities.
sensible (adj.): late 14c., "capable of sensation or feeling;" also "capable of being sensed or felt, perceptible to the senses," hence "easily understood; logical, reasonable," from Late Latin sensibilis "having feeling: perceptible by the senses," from sensus, past participle of sentire "perceive, feel" (see sense (n.)). Of persons, "aware, cognizant (of something)" early 15c.; "having good sense, capable of reasoning, discerning, clever," mid-15c. Of clothes, shoes, etc., "practical rather than fashionable" it is attested from 1855.

Other Middle English senses included "susceptible to injury or pain" (early 15c., now gone with sensitive); "worldly, temporal, outward" (c. 1400); "carnal, unspiritual" (early 15c., now gone with sensual). Related: Sensibleness.
sensibly (adv.): early 15c., "in a manner perceived to the senses," from sensible + -ly (2). Meaning "with good sense" is attested from 1755.
sensitive (adj.): late 14c., in reference to the body or its parts, "having the function of sensation;" also (early 15c.) "pertaining to the faculty of the soul that receives and analyzes sensory information;" from Old French sensitif "capable of feeling" (13c.) and directly from Medieval Latin sensitivus "capable of sensation," from Latin sensus, past participle of sentire "feel perceive" (see sense (n.)).

Meaning "easily affected" (with reference to mental feelings) first recorded 1816; meaning "having intense physical sensation" is from 1849. Original meaning is preserved in sensitive plant (1630s), which is "mechanically irritable in a higher degree than almost any other plant" [Century Dictionary]. Meaning "involving national security" is recorded from 1953. Related: Sensitively; sensitiveness.
sensitivity (n.): 1803, from sensitive + -ity. Sensitivity training attested by 1954.
sensitization (n.): 1862, originally in photography, noun of action from sensitize.
sensitize (v.): 1856, in photography; see sensitive + -ize. Of persons from 1880. Related: Sensitized; sensitizing.
sensor (n.): 1947, from an adjective (1865), a shortened form of sensory (q.v.).
sensorimotor: "pertaining to sensation and to motion," 1855, from comb. form of sensory + motor (n.).
sensorium (n.): "seat of the soul" in the brain, 1640s, from Late Latin sensorium, from sens-, past participle stem of sentire "to feel" (see sense (n.)) + -orium (see -ory).
sensory (adj.): 1749, "pertaining to sense or sensation," from Latin sensorius, from sensus, past participle of sentire "to perceive, feel" (see sense (n.)).
sensual (adj.): early 15c., "carnal, unspiritual;" mid-15c., "of or pertaining to the senses," from Middle French sensuel (15c.) and directly from Late Latin sensualis "endowed with feeling" (see sensuality). Meaning "connected with gratification of the senses," especially "lewd, unchaste" is attested from late 15c.
sensualism (n.): 1803, "the philosophical doctrine that the senses are the sole source of knowledge," from sensual + -ism. From 1813 as "addiction to sensual indulgence."
sensualist (n.): 1660s, from sensual + -ist.
sensuality (n.): mid-14c., "the part of man that is concerned with the senses," from Old French sensualite "the five senses; impression," from Late Latin sensualitatem (nominative sensualitas) "capacity for sensation," from Latin sensualis "endowed with feeling, sensitive," from sensus "feeling" (see sense (n.)). Chiefly "animal instincts and appetites," hence "the lower nature regarded as a source of evil, lusts of the flesh" (1620s).
sensualize (v.): 1680s, from sensual + -ize. Related: Sensualized; sensualizing.
sensuous (adj.): 1640s, "pertaining to the senses" apparently coined by Milton to recover the original meaning of sensual and avoid the lascivious connotation that the older word had acquired, but by 1870 sensuous, too, had begun down the same path and come to mean "alive to the pleasures of the senses." Rare before Coleridge popularized it "To express in one word all that appertains to the perception, considered as passive and merely recipient ...." (1814). From Latin sensus (see sense (n.)) + -ous. Related: Sensuously; sensuousness.
Sensurround: 1974, proprietary name for movie special effects apparatus, coined from sense (n.) + surround.
sentence (n.): c. 1200, "doctrine, authoritative teaching; an authoritative pronouncement," from Old French sentence "judgment, decision; meaning; aphorism, maxim; statement of authority" (12c.) and directly from Latin sententia "thought, way of thinking, opinion; judgment, decision," also "a thought expressed; aphorism, saying," from sentientem, present participle of sentire "be of opinion, feel, perceive" (see sense (n.)). Loss of first -i- in Latin by dissimilation.

From early 14c. as "judgment rendered by God, or by one in authority; a verdict, decision in court;" from late 14c. as "understanding, wisdom; edifying subject matter." From late 14c. as "subject matter or content of a letter, book, speech, etc.," also in reference to a passage in a written work. Sense of "grammatically complete statement" is attested from mid-15c. "Meaning," then "meaning expressed in words." Related: Sentential.
sentence (v.): "to pass judgment," c. 1400, from sentence (n.). Related: Sentenced; sentencing.
sententious (adj.): mid-15c., "full of meaning," from Middle French sententieux, from Latin sententiosus "full of meaning, pithy," from sententia "thought; expression of a thought" (see sentence (n.)). Meaning "addicted to pompous moralizing" first recorded 1590s. Related: Sententiously; sententiousness.
sentience (n.): 1817, "faculty of sense; feeling, consciousness;" see sentient + -ence. Related: Sentiency (1796).
sentient (adj.): 1630s, "capable of feeling," from Latin sentientem (nominative sentiens) "feeling," present participle of sentire "to feel" (see sense (n.)). Meaning "conscious" (of something) is from 1815.
sentiment (n.): late 14c., sentement, "personal experience, one's own feeling," from Old French sentement (12c.), from Medieval Latin sentimentum "feeling, affection, opinion," from Latin sentire "to feel" (see sense (n.)).

Meaning "what one feels about something" (1630s) and modern spelling seem to be a re-introduction from French (where it was spelled sentiment by 17c.). A vogue word mid-18c. with wide application, commonly "a thought colored by or proceeding from emotion" (1762), especially as expressed in literature or art. The 17c. sense is preserved in phrases such as my sentiments exactly.
sentimental (adj.): 1749, "pertaining to or characterized by sentiment," from sentiment + -al (1). At first without pejorative connotations; meaning "having too much sentiment, apt to be swayed by prejudice" had emerged by 1793 (implied in sentimentalist). Related: Sentimentally.
sentimentalism (n.): 1801, from sentimental + -ism.
sentimentalist (n.): 1768, from sentimental + -ist.
sentimentality (n.): 1768, from sentimental + -ity.
sentimentalize (v.): 1764, intransitive, "indulge in sentiments," from sentimental + -ize. Meaning "to make sentimental" (transitive) is from 1813. Related: Sentimentalized; sentimentalizing.
Think on these things, and let S______ go to Lincoln sessions by himself, and talk classically with country justices. In the meantime we will philosophize and sentimentalize;--the last word is a bright invention of the moment in which it was written, for yours or Dr. Johnson's service .... [Laurence Sterne, letter to William Combe, Esq., dated Aug. 5, 1764, published 1787]
sentinel (n.): 1570s, from Middle French sentinelle (16c.), from Italian sentinella "a sentinel." OED says "No convincing etymology of the It. word has been proposed," but perhaps (via a notion of "perceive, watch"), from sentire "to hear," from Latin sentire "feel, perceive by the senses" (see sense (n.)).
sentry (n.): 1610s, originally "watchtower;" perhaps a shortened variant of sentinel, which had a variant form centrinel (1590s); or perhaps worn down from sanctuary, on notion of "shelter for a watchman." Meaning "military guard posted around a camp" is first attested 1630s. Sentry-box is from 1728.
Seoul: South Korean capital, from Korean soul, literally "capital." It was the national capital from 1392 until Japanese annexation in 1910.
sepal (n.): "leaf of the calyx," 1821, from French sépal, from Modern Latin sepalum (H.J. de Necker, 1790), coined from Latin separatus "separate, distinct" (see separate (v.)) + petalum "petal" (see petal).
separable (adj.): late 14c., from Latin separabilis, from separare (see separate (v.)). Related: Separability.
separate (v.): late 14c., from Latin separatus, past participle of separare "to pull apart," from se- "apart" (see secret) + parare "make ready, prepare" (see pare). Sever (q.v.) is a doublet, via French. Related: Separated; separating.
separate (adj.): "detached, kept apart," c. 1600, from separate (v.) or from Latin separatus. Separate but equal in reference to U.S. segregation policies on railroads is attested from 1888. Separate development, official name of apartheid in South Africa, is from 1955. Related: Separately (1550s); separateness.
Frequently the colored coach is little better than a cattle car. Generally one half the smoking car is reserved for the colored car. Often only a cloth curtain or partition run half way up separates this so-called colored car from the smoke, obscene language, and foul air of the smokers' half of the car. All classes and conditions of colored humanity, from the most cultured and refined to the most degraded and filthy, without regard to sex, good breeding or ability to pay for better accommodation, are crowded into this separate, but equal (?) half car. [Rev. Norman B. Wood, "The White Side of a Black Subject," 1897]
separated (adj.): 1530s, past participle adjective from separate (v.). In reference to married couples deciding to live apart, from 1878.
separates (n.): "articles of (women's) clothing that may be worn in various combinations," 1945, from separate (adj.). As a noun, separate is attested from 1610s in the sense "separatist."
separation (n.): c. 1400, from Old French separacion (Modern French séparation), from Latin separationem (nominative separatio) noun of action from past participle stem of separare (see separate (v.)). Specific sense of "sundering of a married couple" is attested from c. 1600. Sense in photography is from 1922. Separation of powers first recorded 1788, in "Federalist" (Hamilton), from French séparée de la puissance (Montesquieu, 1748). Separation anxiety first attested 1943.