Online Etymology Dictionary

helpless (adj.): "unable to act for oneself," c. 1200, from help (n.) + -less. Related: Helplessly; helplessness. In Middle English and later sometimes "unable to give help, affording no help" (late 14c.), but this never was common.
helpmate (n.): "companion," 1715, altered from helpmeet.
helpmeet (n.): a ghost word from the 1611 translation of the Bible, where it originally was a two-word noun-adjective phrase translating Latin adjutorium simile sibi [Gen. ii:18] as "an help meet for him," and meaning literally "a helper like himself." See help (n.) + meet (adj.). By 1670s it was hyphenated help-meet and mistaken as a modified noun. Compare helpmate. The original Hebrew is 'ezer keneghdo.
helter-skelter (adv.): also helter skelter, 1590s, perhaps a rhyming reduplication from skelte "to hasten, scatter hurriedly," or merely "a riming formula vaguely imitative of hurry and confusion" [Century Dictionary] as in harum-scarum, etc. As an adjective from 1785.
helve (n.): Old English helfe, hielfe "handle of an axe" or other tool or weapon, from Proto-Germanic *halbma- (source also of Old Saxon helvi, Middle Dutch helf, Old High German halb "handle of an axe," Old High German helmo "tiller"); related to halter and helm (n.1), from PIE *kelp- "to hold, grasp." In Middle English, to holden the axe bi the helve (c. 1200) meant "to take something by the right end."
Helvetian (adj.): "Swiss," 1550s, from Helvetia terra, Medieval Latin name of Switzerland, from Latin Helvetius "pertaining to the Helvetii," a Celtic people of ancient Gallia Lugdunensis. Related: Helvetic.
hem (n.): Old English hem "a border" of cloth or a garment, from Proto-Germanic *hamjam (source also of Old Norse hemja "to bridle, curb," Swedish hämma "to stop, restrain," Old Frisian hemma "to hinder," Middle Dutch, German hemmen "to hem in, stop, hinder"), from PIE *kem- "to compress" (source also of Armenian kamel "to press, squeeze," Lithuanian kamuoti "press together, stop," Russian kom "mass, clot, clod").

Apparently the same root yielded Old English hamm, common in place names (where it means "enclosure, land hemmed in by water or high ground, land in a river bend"). In Middle English, hem also was a symbol of pride or ostentation.
If þei wer þe first þat schuld puplysch þese grete myracles of her mayster, men myth sey of hem, as Crist ded of þe Pharisees, þat þei magnified her owne hemmys. [John Capgrave, "Life of Saint Gilbert of Sempringham," 1451]
hem (interj.): 1520s, probably imitative of the sound of clearing the throat; late 15c. as a verb meaning "to make the sound 'hem.'" Hem and haw (v.) first recorded 1786, with haw "hesitation" (1630s; see haw (v.)); hem and hawk attested from 1570s.
hem (v.): late 14c., "to provide (something) with a border or fringe" (surname Hemmer attested from c. 1300), from hem (n.). Meaning "to enclose, circumscribe" is from 1530s. Related: Hemmed; hemming. The phrase hem in "shut in, confine," first recorded 1530s.
hem-stitch (n.): also hemstitch, 1821, from hem + stitch (n.). Adjective hem-stitched is from 1813. Related: Hem-stitching.
hematite (n.): 1540s, haematites, from Middle French hematite (16c.), from Latin haematites, from Greek haimatites lithos "bloodlike stone," from haima (genitive haimatos) "blood" (see -emia). Earlier in English as emachite (late 14c.).
hemato-: also haemato-, before vowels hemat-, haemat-, word-forming element in scientific compounds meaning "blood," from Greek haimato-, comb. form of haima (genitive haimatos) "blood" (see -emia). Compare hemo-.
hematoma (n.): also haematoma, 1826, from hemato- + -oma.
hemi-: word-forming element meaning "half," from Latin hemi- and directly from Greek hemi- "half," from PIE root *semi-, which is the source of Sanskrit sami, Latin semi- (see semi-), Old High German sami- "half," and Old English sam-, denoting a partial or imperfect condition (see sandblind).
hemidemisemiquaver (n.): "sixty-fourth note" in music, 1848, from hemi- + demi- + semi- + quaver (n.).
Hemingwayesque (adj.): 1934, in reference to American writer Ernest Hemingway (1899-1961). With -esque.
hemisphere (n.): late 14c., hemysperie, in reference to the celestial sphere, from Late Latin hemisphaerium, from Greek hemisphairion, from hemi- "half" (see hemi-) + sphaira "sphere" (see sphere). Spelling reformed 16c. Of the Earth, from 1550s; of the brain, 1804.
hemispheric (adj.): 1580s, from hemisphere + -ic.
hemistich (n.): "half a poetic line," 1570s, from Middle French hémistiche (16c.) or directly from Late Latin hemistichium, from Greek hemistikhion "half-line, half-verse," from hemi- "half" (see hemi-) + stikhos "row, line of verse," from PIE *stigho-, suffixed form of root *steigh- "to stride, step, rise" (see stair). Related: Hemistichal.
hemline (n.): also hem-line, 1899, from hem (n.) + line (n.).
hemlock (n.): poisonous plant native to Europe, transplanted to North America, Old English (Kentish) hemlic, earlier hymlice, hymblice, name of a poisonous plant; of unknown origin. Liberman suggests from root hem- "poison," perhaps with the plant name suffix -ling or -ig. As the name of the poison derived from the plant, c. 1600. The North American fir tree so called by 1670s in New England, from resemblance of the position and tenuity of its leaves to those of the plant.
hemo-: word-forming element meaning "blood," perhaps via Old French hemo-, Latin haemo-, from Greek haimo-, contraction of haimato-, comb. form of haima "blood" (see -emia).
hemoglobin (n.): also hæmoglobin, coloring matter in red blood cells, 1862, shortening of hæmatoglobin (1845), from Greek haimato-, comb. form of haima (genitive haimatos) "blood" (see -emia) + globulin, a type of simple protein, from globule, formerly a word for "corpuscle of blood."
hemophilia (n.): 1848 (also sometimes in Englished form hæmophily), from German hämophile, coined 1828 by German physician Johann Lucas Schönlein (1793-1864), from Greek haima "blood, bloodshed, streams of blood" (see -emia) + philia "to love" (see -philia), here with a sense of "tendency to."
hemophiliac: 1894 (adj.); 1891 (n.), from hemophilia. Perhaps modeled on French hémophilique (1878).
hemophobia (n.): 1844, from hemo- "blood" + -phobia "fear." Perhaps based on French hémophobie. Originally in reference to fear of medical blood-letting.
hemorrhage (n.): c. 1400, emorosogie (modern form by 17c.), from Latin haemorrhagia, from Greek haimorrhagia, from haimorrhages "bleeding violently," from haima "blood" (see -emia) + rhage "a breaking," from rhegnynai "to break, burst." Related: Hemorrhagic.
hemorrhage (v.): by 1882, from hemorrhage (n.). Related: Hemorrhaged; hemorrhaging.
Slang in Reports: B.I.D. for "Brought in Dead" and "Dotty" are, [Mr. Sidney Holland of London Hospital] considers, permissible expressions, but he draws the line at "fitting" and "hæmorrhaging." Only such terms, he says, should be used as outside doctors will understand. We would say that on a point of such odiously bad taste he might have been much more severe. [Lavinia L. Dock, "The American Journal of Nursing," 1906]
hemorrhoid (n.): see hemorrhoids.
hemorrhoids (n.): plural of hemorrhoid; late 14c., emeroudis, from Old French emorroides (13c.), from Latin hæmorrhoidae, from Greek haimorrhoides (phlebes) "(veins) liable to discharge blood," plural of haimorrhois, from haima "blood" (see -emia) + rhoos "a stream, a flowing," from rhein "to flow" (see rheum). Related: Hemmorhoidal.
hemp (n.): Old English hænep "hemp, cannabis sativa," from Proto-Germanic *hanapiz (source also of Old Saxon hanap, Old Norse hampr, Old High German hanaf, German Hanf), probably a very early Germanic borrowing of the same Scythian word that became Greek kannabis (see cannabis). As the name of the fiber made from the plant, by c. 1300. Slang sense of "marijuana" dates from 1940s; scientific applications for the narcotic derived from hemp date to 1870.
hempen (adj.): "made of hemp," late 14c., from hemp + -en (2). In many figurative expressions 15c.-19c. it is in reference to the hangman's noose.
hen (n.): Old English henn "hen," from West Germanic *hannjo (source also of Old Frisian henn, Middle Dutch henne, Old High German henna), fem. of *han(e)ni "male fowl, cock" (source of Old English hana "cock"), literally "bird who sings (for sunrise)," from PIE root *kan- "to sing" (see chant).

The original masculine word survives in German (Hahn "cock"), Swedish, Danish, etc. German also has a generic form, Huhn, for either gender of the bird. Extension to "female of any bird species" is early 14c. in English. Hen as slang for "woman" dates from 1620s; hence hen party "gathering of women," first recorded 1887. To be mad as a wet hen is from 1823, but the figure was used to indicate other states:
Some, on the contrary, are viciously opposite to these, who act so tamely and so coldly, that when they ought to be angry, to thunder and lighten, as one may say, they are no fuller of Heat, than a wet Hen, as the Saying is; .... ["Life of Mr. Thomas Betterton," London, 1710]

Orth. Out upon you for a dastardly Fellow; you han't the Courage of a wet Hen. ["A Sermon Preached at St. Mary-le-Bow, March 27, 1704"]
As wanton as a wet hen is in "Scots Proverbs" (1813). Among Middle English proverbial expressions was nice as a nonne hen "over-refined, fastidiously wanton" (c. 1500); to singen so hen in snowe "sing miserably," literally "sing like a hen in snow" (c. 1200). The figure of the hen with one chick dates to 1590s. Hen's teeth as a figure of scarceness is attested by 1838.
hen-house (n.): 1510s, from hen + house (n.). As a place cheifly inhabited or ruled by women, from 1785.
henbane (n.): poisonous Eurasian plant, mid-13c., from hen (n.) + bane (n.).
hence (adv.): "(away) from here," late 13c., hennes, with adverbial genitive -s + Old English heonan "away, hence," from West Germanic *hin- (source also of Old Saxon hinan, Old High German hinnan, German hinnen), from PIE *ki-, variant of root *ko- "this," the stem of the demonstrative pronoun (see here).

The modern spelling (mid-15c.) is phonetic, to retain the breathy -s- (compare twice, once, since). Original "away from this place;" of time, "from this moment onward," late 14c.; meaning "from this (fact or circumstance)" first recorded 1580s. Wyclif (1382) uses hennys & þennys for "from here and there, on both sides."
henceforth (adv.): late 14c., earlier henne forth (late Old English); see hence + forth.
henceforward (adv.): late 14c., from hence + forward (adv.). Related: Henceforwards.
henchman (n.): mid-14c., hengestman, later henshman (mid-15c.) "high-ranking servant (usually of gentle birth), attendant upon a king, nobleman, etc.," originally "groom," probably from man (n.) + Old English hengest "horse, stallion, gelding," from Proto-Germanic *hangistas (source also of Old Frisian hengst, Dutch hengest, German Hengst "stallion"), perhaps literally "best at springing," from PIE *kenku- (source also of Greek kekiein "to gush forth;" Lithuanian sokti "to jump, dance;" Breton kazek "a mare," literally "that which belongs to a stallion").

Perhaps modeled on Old Norse compound hesta-maðr "horse-boy, groom." The word became obsolete in England 17c., but it was retained in Scottish as "personal attendant of a Highland chief," in which sense Scott revived it in literary English from 1810. Sense of "obedient or unscrupulous follower" is first recorded 1839, probably somehow a misunderstanding of the word as used by Scott.
This officer is a sort of secretary, and is to be ready, upon all occasions, to venture his life in defence of his master; and at drinking-bouts he stands behind his seat, at his haunch, from whence his title is derived, and watches the conversation, to see if any one offends his patron. [Scott, notes to "Lady of the Lake," 1820; his proposed etymology is not now considered correct]
hendeca-: word-forming element meaning "eleven," from Latinized form of Greek hendeka "eleven," from hen, neuter of heis "one," from PIE *hems-, from root *sem- (1) "one" (see same) + deka "ten" (see ten).
hendiadys (n.): 1580s, figure of speech in which two nouns joined by and are used in place of a noun and an adjective; from Medieval Latin alteration of Greek hen dia dyoin "one (thing) by means of two." If this term was used by Greek grammarians it is no longer found in their writings, but it is frequent among Latin writers.
henge (n.): 1740, noted as a Yorkshire word for hanging rocks (see Stonehenge).
Henley: town on the Thames in Oxfordshire, site of annual regatta since 1839. The name is Old English hean-leage "(settlement) at or by the high wood."
henna (n.): c. 1600, "dye or cosmetic from the henna plant," from Arabic hinna, name for the small thorny tree (Egyptian Privet), the leaves of which are used to make the reddish dye for the body or hair; said to be of Persian origin, from Arabic. Related: Hennaed (1860).
Hennessey: Irish surname, from O'(h)Aonghusa "descendant of Aonghus" ("one-choice").
henotheism (n.): "devotion to a single god without asserting that he or she is the only god," 1860, from Greek henos, neuter of heis "one" (from PIE *sem- (1) "one, as one;" see same) + theism. Coined by (Friedrich) Max Müller (1823-1900), professor of comparative philology at Oxford. Supposedly a characteristic of the oldest Hindu religion; or a system between monotheism and polytheism. Related: Henotheist; henotheistic.
henpecked (adj.): said of a husband whose wife rules him by superior force of will, 1670s, an image from hen + peck (v.).
The henpect Man rides behind his Wife, and lets her wear the Spurs and govern the Reins. [Samuel Butler, "Genuine Remains," 1759]
The verb henpeck (1680s) apparently is a back-formation.
Henrietta: fem. proper name, from French Henriette, fem. diminutive of Henri (see Henry). In late 19c. a type of light dress fabric.
Henry: masc. proper name, from French Henri, from Late Latin Henricus, from German Heinrich, from Old High German Heimerich, literally "the ruler of the house," from heim "home" (see home (n.)) + rihhi "ruler" (see Reich). One of the most popular Norman names after the Conquest. Related: Henrician.
heortology (n.): "study of religious feasts and calendars," 1881, from Greek heorte "a feast or festival, holiday," + -ology. The immediate source of the English word is in French or German. Related: Heortological (1880).