sickly (adj.) Look up sickly at Dictionary.com
late 14c., "ill, invalid, habitually ailing," from sick (adj.) + -ly (1). Meaning "causing sickness" in any sense is from c.1600. Related: Sickliness.
sickness (n.) Look up sickness at Dictionary.com
Old English seocnes "sickness, disease; a disease;" see sick (adj.) and -ness.
sicko (n.) Look up sicko at Dictionary.com
1977, from sick (adj.) in the mental sense + ending as in weirdo. Sickie "a pervert" is attested from 1972; sicknik (1959) "pervert, obscene comedian" (applied to Lenny Bruce) has fad ending -nik.
siddha (n.) Look up siddha at Dictionary.com
in Indian religion, "one who has attained perfection and bliss," 1846, from Sanskrit siddhah "accomplished, achieved, successful, possessing supernatural power, sorcerer, saint," related to sidhyati "reaches his goal, succeeds," sadhuh "right, skilled, excellent, a holy man."
side (n.) Look up side at Dictionary.com
Old English side "flanks of a person, the long part or aspect of anything," from Proto-Germanic *sithon (cognates: Old Saxon sida, Old Norse siða, Danish side, Swedish sida, Middle Dutch side, Dutch zidje, Old High German sita, German Seite), from adjective *sithas "long" (source of Old English sid "long, broad, spacious," Old Norse siðr "long, hanging down"), from PIE root *se- "long, late" (see soiree).

Original sense preserved in countryside. Figurative sense of "position or attitude of a person or set of persons in relation to another" (as in choosing sides) first recorded mid-13c. Meaning "one of the parties in a transaction" is from late 14c.; sense in a sporting contest or game is from 1690s. Meaning "music on one side of a phonograph record" is first attested 1936. Phrase side by side "close together and abreast" is recorded from c.1200. Side-splitting "affecting with compulsive laughter" is attested by 1825.
side (v.) Look up side at Dictionary.com
late 15c., "to cut into sides" (of meat), from side (n.). Meaning "to support one of the parties in a discussion, dispute, etc.," is first attested 1590s, from side (n.) in the figurative sense; earlier to hold sides (late 15c.). Related: Sided; siding.
side (adj.) Look up side at Dictionary.com
late 14c., from side (n.).
side effect (n.) Look up side effect at Dictionary.com
also side-effect, 1884, from side (adj.) + effect (n.). Medical use, with reference to drugs, is recorded from 1939.
side-dish (n.) Look up side-dish at Dictionary.com
1725, from side (adj.) + dish (n.). Restaurant phrase on the side "apart from the main dish" is attested from 1884, American English.
side-door (n.) Look up side-door at Dictionary.com
1530s, from side (n.) + door.
side-saddle (n.) Look up side-saddle at Dictionary.com
"saddle made for the occupant to ride on with both feet on the same side of the horse," used chiefly by women, late 15c., from side (adj.) + saddle (n.).
side-swipe (v.) Look up side-swipe at Dictionary.com
also sideswipe, "to strike with a glancing blow," 1904, from side (adj.) + swipe (v.). Related: Side-swiped; side-swiping. The noun is first recorded 1917.
side-table (n.) Look up side-table at Dictionary.com
late 14c., from side (n.) + table (n.).
side-way (n.) Look up side-way at Dictionary.com
also sideway, 1550s, lateral space for passage or movement," from side (n.) + way (n.).
sidearm (adj.) Look up sidearm at Dictionary.com
also side-arm, 1908, from side (adj.) + arm (n.1).
sidearms (n.) Look up sidearms at Dictionary.com
also side-arms, 1760, from side (adj.) + plural of arm (n.2).
sidebar (n.) Look up sidebar at Dictionary.com
"secondary article accompanying a larger one in a newspaper," 1948, from side (adj.) + bar (n.1).
sideboard (n.) Look up sideboard at Dictionary.com
"table placed near the side of a room or hall" (especially one where food is served), c.1300, from side (adj.) + board (n.1).
sideburns (n.) Look up sideburns at Dictionary.com
1880, American English, alteration of burnsides (q.v).
sidekick (n.) Look up sidekick at Dictionary.com
also side-kick, "companion or close associate," 1901, also side-kicker (1903), American English, of unknown origin. Earlier terms were side-pal (1886), side-partner (1886).
sidelight (n.) Look up sidelight at Dictionary.com
also side-light, c.1600, "light coming from the side," from side (adj.) + light (n.). Figurative meaning "incidental information on a subject" is attested from 1862.
sideline (n.) Look up sideline at Dictionary.com
also side-line, "line on the side of a fish," 1768; "lines marking the limits of playing area" (on a football field, etc.), 1862, from side (adj.) + line (q.v.). Meaning "course of business aside from one's regular occupation" is from 1890. Railway sense is from 1890. The figurative sense of "position removed from active participation" is attested from 1934 (from the railway sense or from sports, because players who are not in the game stand along the sidelines). The verb meaning "put out of play" is from 1945. Related: Sidelined; sidelining.
sidelong (adv.) Look up sidelong at Dictionary.com
"towartd the side," 1570s, alteration of Middle English sidlyng (see sidle), probably by influence of side (n.) + long (adj.). As an adjective from 1590s.
sideman (n.) Look up sideman at Dictionary.com
"supporting musician," 1936, from side (adj.) + man (n.). Earlier it meant "assistant to a church warden" (1560s).
sidenote (n.) Look up sidenote at Dictionary.com
1776, from side (adj.) + note (n.).
sidereal (adj.) Look up sidereal at Dictionary.com
also siderial, 1630s, "star-like;" 1640s, "of or pertaining to the stars," earlier sideral (1590s), from French sidereal (16c.), from Latin sidereus "starry, astral, of the constellations," from sidus (genitive sideris) "star, group of stars, constellation," probably from PIE root *sweid- "to shine" (cognates: Lithuanian svidus "shining, bright"). Sidereal time is measured by the apparent diurnal motion of the fixed stars. The sidereal day begins and ends with the passage of the vernal equinox over the meridian and is about four minutes shorter than the solar day, measured by the passage of the sun over the meridian.
sideshow (n.) Look up sideshow at Dictionary.com
also side-show, 1855, "minor exhibition alongside or near a principal one," apparently a coinage of P.T. Barnum's, from side (adj.) + show (n.). Hence, any diversion or distracting event.
sidestep (n.) Look up sidestep at Dictionary.com
also side-step, 1757, "a stepping to the side" (originally in military drill), from side (adj.) + step (n.). The verb is recorded from 1895; the figurative sense is attested from 1900.
sidetrack (n.) Look up sidetrack at Dictionary.com
also side-track, "railway siding," 1835, from side (adj.) + track (n.). The verb meaning "to move (a train car) onto a sidetrack" is from 1874; figurative sense of "to divert from the main purpose" is attested from 1881. Related: Sidetracked.
sidewalk (n.) Look up sidewalk at Dictionary.com
"path for pedestrians on the side of a street," 1739, from side (adj.) + walk (n.). The use of sidewalk for pavement as one of the characteristic differences between American and British English has been noted since at least 1902.
sideways (adv.) Look up sideways at Dictionary.com
1570s, from side (n.) + way (n.), with adverbial genitive. To look sideways "cast scornful glances" is recorded from 1844.
sidewinder (n.) Look up sidewinder at Dictionary.com
small horned rattlesnake of southwestern U.S., 1875, American English, from side (adj.) + agent noun of wind (v.), so called in reference to its "peculiar lateral progressive motion." Also sidewiper (1888).
Sidhe Look up Sidhe at Dictionary.com
"the hills of the fairies," 1793; but in Yeats, "the fairie folk" (1899), elipsis of Irish (aos) sidhe "people of the faerie mound" (compare second element in banshee).
siding (n.) Look up siding at Dictionary.com
c.1600, "a taking of sides in a conflict or debate," verbal noun from side. First attested 1825 in the railroad sense; 1829, American English, in the architectural sense of "boarding on the sides of a building."
sidle (v.) Look up sidle at Dictionary.com
"to move or go sideways," 1690s, back-formation from obsolete Middle English sidlyng (adv.) "obliquely, sideways; aslant; laterally" (early 14c., perhaps in Old English), from side (n.) + adverbial suffix -ling; altered on analogy of verbs ending in -le. Related: Sidled; sidling. Old English had sidlingweg (n.) "sidelong-way, oblique road."
Sidon Look up Sidon at Dictionary.com
ancient Phoenician city, from Greek Sidon, from Phoenician Tzidhon, literally "fishing place," from tzud "to hunt, to capture." Related: Sidonian.
SIDS (n.) Look up SIDS at Dictionary.com
1970, acronym for Sudden Infant Death Syndrome.
Sieg Heil (interj.) Look up Sieg Heil at Dictionary.com
Nazi salute, German, literally "hail victory;" from German Sieg "victory," from Old High German sigu (see Siegfried), second element from Proto-Germanic *hailitho (see health).
siege (n.) Look up siege at Dictionary.com
early 13c., "a seat" (as in Siege Perilous, early 13c., the vacant seat at Arthur's Round Table, according to prophecy to be occupied safely only by the knight destined to find the Holy Grail), from Old French sege "seat, throne," from Vulgar Latin *sedicum "seat," from Latin sedere "sit" (see sedentary). The military sense is attested from c.1300; the notion is of an army "sitting down" before a fortress.
Siegfried Look up Siegfried at Dictionary.com
masc. proper name, German Siegfried, first element from Old High German sigu "victory," from Proto-Germanic *sigiz- "victory" (cognates: Old Frisian si, Old Saxon sigi, Middle Dutch seghe, Dutch zege, German Sieg, Old Norse sigr, Danish seier, Gothic sigis, Old English sige "victory, success, triumph"), from PIE root *segh- "to have, to hold" (cognates: Sanskrit saha- "victory," sahate "overcomes, masters;" see scheme (n.)).

Second element from Old High German frithu "peace," from PIE *pri-tu-, from root *pri- "to love" (see free (adj.)). Siegfried Line, World War I German fortifications in France, is from German Siegfriedlinie, named for the hero in Wagner's "Ring" cycle.
Sienna Look up Sienna at Dictionary.com
city in central Italy, probably from Senones, the name of a Gaulish people who settled there in ancient times. Related: Sienese. The brownish-ochre color (1760) is from Italian terra di Sienna "earth of Siena," where the coloring material first was produced.
sierra (n.) Look up sierra at Dictionary.com
"a range of hills," 1610s, from Spanish sierra "jagged mountain range," literally "saw," from Latin serra "a saw" (compare serrated), which is of unknown origin.
Sierra Leone Look up Sierra Leone at Dictionary.com
West African nation, literally "lion mountains," from Spanish sierra "mountain range" (see sierra) + leon "lion" (see lion). Attested from mid-15c. in Portuguese explorers' accounts, and a very early explanation of the name derives it from the "roaring" of thunder in the mountains. Related: Sierra Leonean.
siesta (n.) Look up siesta at Dictionary.com
"mid-day nap," 1650s, from Spanish siesta, from Latin sexta (hora) "sixth (hour)," the noon of the Roman day (coming six hours after sunrise), from sexta, fem. of sextus "sixth" (see Sextus).
sieve (n.) Look up sieve at Dictionary.com
Old English sife "sieve," from Proto-Germanic *sib (cognates: Middle Dutch seve, Dutch zeef, Old High German sib, German Sieb), from PIE *seib- "to pour out, sieve, drip, trickle" (see soap (n.)). Related to sift. The Sieve of Eratosthenes (1803) is a contrivance for finding prime numbers. Sieve and shears formerly were used in divinations.
sieve (v.) Look up sieve at Dictionary.com
late 15c., from sieve (n.). Related: Sieved; sieving.
sift (v.) Look up sift at Dictionary.com
Old English siftan "pass (something) through a sieve," from Proto-Germanic *sib- (cognates: Dutch ziften, Middle Low German sichten, German sichten "to sift;" see sieve (n.)). Intransitive sense "to pass loosely or fall scatteredly" is from 1590s. Metaphoric sense of "look carefully through" first recorded 1530s. Related: Sifted; sifting.
sifter (n.) Look up sifter at Dictionary.com
1570s, agent noun from sift (v.).
sig (n.) Look up sig at Dictionary.com
abbreviation of signature, 1866.
sigh (v.) Look up sigh at Dictionary.com
mid-13c., probably a Middle English back-formation from sighte, past tense of Old English sican "to sigh," perhaps echoic of the sound of sighing. Related: Sighed; sighing.