Jupiter (n.) Look up Jupiter at Dictionary.com
c.1200, "supreme deity of the ancient Romans," from Latin Iupeter, from PIE *dyeu-peter- "god-father" (originally vocative, "the name naturally occurring most frequently in invocations" [Tucker]), from *deiw-os "god" (see Zeus) + peter "father" in the sense of "male head of a household" (see father). Compare Greek Zeu pater, vocative of Zeus pater "Father Zeus;" Sanskrit Dyauspita "heavenly father." The planet name is attested from late 13c. Jupiter Pluvius "Jupiter as dispenser of rain" was used jocularly from 1864.
Jurassic (adj.) Look up Jurassic at Dictionary.com
in reference to "geological period between the Triassic and the Cretaceous," 1847, from French Jurassique, literally "of the Jura Mountains," between France and Switzerland, whose limestones were laid down during this geological period. Used in English in a literal sense "pertaining to the Jura Mountains" by 1831. The name is said to be from Gaulish *iuris "wooded mountain."
jurat (n.) Look up jurat at Dictionary.com
"one who has taken an oath," early 15c. (mid-14c. in Anglo-French), from Medieval Latin iuratus, literally "sworn man," noun use of past participle of iurare "to swear" (see jury (n.)).
juridical (adj.) Look up juridical at Dictionary.com
c.1500, from Latin iuridicalis "relating to right; pertaining to justice," from iuridicus, from ius "right, law" (genitive iuris; see jurist) + dicere "to say, to speak" (see diction). Related: Juridically.
jurisdiction (n.) Look up jurisdiction at Dictionary.com
early 14c. "administration of justice" (attested from mid-13c. in Anglo-Latin), from Old French juridiccion (13c.) and directly from Latin iurisdictionem (nominative iurisdictio) "administration of justice, jurisdiction," from ius (genitive iuris; see jurist) "right, law" + dictio "a saying" (see diction). Meaning "extent or range of administrative power" is from late 14c. Related: Jurisdictional.
jurisprudence (n.) Look up jurisprudence at Dictionary.com
1620s, "knowledge of law," from French jurisprudence (17c.) and directly from Late Latin iurisprudentia "the science of law," from iuris "of right, of law" (genitive of ius; see jurist) + prudentia "knowledge, a foreseeing" (see prudence). Meaning "the philosophy of law" is first attested 1756. Related: Jurisprudential.
jurist (n.) Look up jurist at Dictionary.com
mid-15c., "one who practices law," from Middle French juriste (14c.), from Medieval Latin iurista "jurist," from Latin ius (genitive iuris) "law," from PIE *yewes- "law," originally a term of religious cult, perhaps meaning "sacred formula" (compare Latin iurare "to pronounce a ritual formula," Vedic yos "health," Avestan yaoz-da- "make ritually pure," Irish huisse "just").

The Germanic root represented by Old English æ "custom, law," Old High German ewa, German Ehe "marriage," though sometimes associated with this group, seems rather to belong to PIE *ei- "to go." Meaning "a legal writer" is from 1620s.
juror (n.) Look up juror at Dictionary.com
c.1300 (attested from late 12c. in Anglo-Latin), from Anglo-French jurour (late 13c.; Old French jureor), from Latin iuratorem (nominative iurator) "swearer," agent noun from iurare "to swear" (see jury (n.)).
jury (n.) Look up jury at Dictionary.com
early 14c. (attested from late 12c. in Anglo-Latin), from Anglo-French juree (late 13c.), from Medieval Latin iurata "an oath, an inquest," fem. past participle of Latin iurare "to swear," from ius (genitive iuris) "law" (see jurist). Meaning "body of persons chosen to award prizes at an exhibition" is from 1851. Grand jury attested from early 15c. in Anglo-French (le graund Jurre).
jury (adj.) Look up jury at Dictionary.com
"temporary," 1610s, in jury-mast, a nautical term for a temporary mast put in place of one broken or blown away, of uncertain origin. The word perhaps is ultimately from Old French ajurie "help, relief," from Latin adjutare (see aid (n.)).
jus Look up jus at Dictionary.com
French, literally "juice" (see juice).
jussive Look up jussive at Dictionary.com
"grammatical mode expressing command," 1846, from Latin iuss-, past participle stem of iubere "to bid, command," from PIE *yeudh- "to move violently, fight;" + -ive.
just (adj.) Look up just at Dictionary.com
late 14c., "righteous in the eyes of God; upright, equitable, impartial; justifiable, reasonable," from Old French juste "just, righteous; sincere" (12c.), from Latin iustus "upright, equitable," from ius "right," especially "legal right, law," from Old Latin ious, perhaps literally "sacred formula," a word peculiar to Latin (not general Italic) that originated in the religious cults, from PIE root *yewes- "law" (cognates: Avestan yaozda- "make ritually pure;" see jurist). The more mundane Latin law-word lex covered specific laws as opposed to the body of laws. The noun meaning "righteous person or persons" is from late 14c.
just (adv.) Look up just at Dictionary.com
"merely, barely," 1660s, from Middle English sense of "exactly, precisely, punctually" (c.1400), from just (adj.), and paralleling the adverbial use of French juste. Just-so story first attested 1902 in Kipling, from the expression just so "exactly that, in that very way" (1751).
justice (n.) Look up justice at Dictionary.com
mid-12c., "the exercise of authority in vindication of right by assigning reward or punishment;" also "quality of being fair and just," from Old French justice "justice, legal rights, jurisdiction" (11c.), from Latin iustitia "righteousness, equity," from iustus "upright, just" (see just (adj.)). The Old French word had widespread senses, including "uprightness, equity, vindication of right, court of justice, judge." The word began to be used in English c.1200 as a title for a judicial officer. Meaning "right order, equity" is late 14c. Justice of the peace first attested early 14c. In the Mercian hymns, Latin iustitia is glossed by Old English rehtwisnisse. To do justice to (someone or something) "render fully and fairly showing due appreciation" is from 1670s.
justiciable (adj.) Look up justiciable at Dictionary.com
mid-15c., from Old French justisable "amenable to a jurisdiction," from justicier, from Latin iustitia (see justice).
justifiability (n.) Look up justifiability at Dictionary.com
1835, from justifiable + -ity.
justifiable (adj.) Look up justifiable at Dictionary.com
1520s, from Old French justifiable, from justifiier (see justify). Earlier in same sense was justificable (mid-15c.). Related: Justifiably (mid-15c.).
justification (n.) Look up justification at Dictionary.com
late 14c., "administration of justice," from Late Latin iustificationem (nominative iustificatio), noun of action from past participle stem of iustificare (see justify). Meaning "action of justifying" is from late 15c. Theological sense is from 1520s.
justified (adj.) Look up justified at Dictionary.com
1580s, "made right," past participle adjective from justify. Typesetting sense is from 1670s.
justify (v.) Look up justify at Dictionary.com
c.1300, "to administer justice;" late 14c., "to show (something) to be just or right," from Old French justifiier "submit to court proceedings" (12c.), from Latin iustificare "act justly toward, make just," from iustificus "dealing justly, righteous," from iustus "just" (see just (adj.)) + root of facere "to do" (see factitious). Of circumstances, "to afford justification," from 1630s. Meaning "to make exact" (now largely restricted to typesetting) is from 1550s. Related: Justified; justifying.
Justin Look up Justin at Dictionary.com
masc. proper name, from Latin Iustinus, literally "just," from iustus (see just (adj.)).
Justine Look up Justine at Dictionary.com
fem. proper name, fem. of Latin Iustinus (see Justin).
justly (adv.) Look up justly at Dictionary.com
early 14c., "in an adjacent position, closely," from just (adj.) + -ly (2). Meanings "truthfully, honestly," "in an equitable manner, with justice, fairly" are from late 14c. Sense of "justifiably, with good reason" is from c.1400; that of "legally, legitimately, rightfully" is early 15c.
justness (n.) Look up justness at Dictionary.com
early 15c., from just (adj.) + -ness.
jut (v.1) Look up jut at Dictionary.com
"to protrude," mid-15c., corruption of obsolete jet (see jetty). Related: Jutted; jutting.
jut (v.2) Look up jut at Dictionary.com
"to strike, hit, push," 1540s, echoic. Related: Jutted; jutting.
jute (n.) Look up jute at Dictionary.com
plant fiber, 1746, from Bengali jhuto, from Sanskrit juta-s "twisted hair," related to jata "braid of hair," of unknown origin, probably from a non-Indo-European language.
Jute Look up Jute at Dictionary.com
Old English Eotas, one of the ancient Germanic inhabitants of Jutland in Denmark; traditionally they were said to have settled in Kent and Hampshire during the 5c. invasion of Britain. The name is related to Old Norse Iotar.
juvenal Look up juvenal at Dictionary.com
1580s (n.), 1630s (adj.), from Latin iuvenalis "of or belonging to youth," from iuvenis "a young person" (see young). The Roman satirist is Decimius Junius Juvenalis.
juvenescence (n.) Look up juvenescence at Dictionary.com
1800; see juvenescent + -ence.
juvenescent (adj.) Look up juvenescent at Dictionary.com
1821, from Latin iuvenescentem (nominative iuvenescens), present participle of iuvenescere "to grow into youth," from iuvenis "young" (see young).
juvenile (adj.) Look up juvenile at Dictionary.com
1620s, from Latin iuvenilis "of or belonging to youth," from iuvenis "young person," originally "young" (compare French jeune; see young). Juvenile delinquency first recorded 1816; Juvenile delinquent the following year.
juvenilia (n.) Look up juvenilia at Dictionary.com
"works of a person's youth," 1620s, from Latin iuvenilia, neuter plural of iuvenilis (see juvenile).
juvenility (n.) Look up juvenility at Dictionary.com
1620s, from Latin iuvenilitas "youth," from iuvenilis (see juvenile).
Juventus Look up Juventus at Dictionary.com
Roman god of youth, personification of iuventas "youth," from iuvenis "a young person" (see young).
juxtapose (v.) Look up juxtapose at Dictionary.com
1851, from French juxtaposer (1835), from Latin iuxta (see juxtaposition) + French poser (see pose (v.1)). Related: Juxtaposed; juxtaposing.
juxtaposition (n.) Look up juxtaposition at Dictionary.com
1660s, from French juxtaposition (1660s), from Latin iuxta "beside, near" + French position (see position (n.)). Latin iuxta is a contraction of *iugista (adv.), superlative of adjective *iugos "closely connected," from stem of iugum "yoke," from iungere "to join" (see jugular).
jynx (n.) Look up jynx at Dictionary.com
"wryneck," 1640s, from Modern Latin jynx (plural jynges), from Latin iynx (see jinx).