1530s, "the giving of thanks," from thanks (n.) + present participle of give (v.). In the specific sense of "public celebration acknowledging divine favors" thanksgiving dates from 1630s (the first one in America was held October 1621 by Plymouth Colony Pilgrims in appreciation of assistance from members of the Massasoit tribe and celebration of the first harvest); though Thanksgiving Day itself is not attested until 1670s.
late 14c., from Old French suplicacion "humble request," from Latin supplicationem (nominative supplicatio) "a public prayer, thanksgiving day," noun of action from past participle stem of supplicare "to beg humbly" (in Old Latin as sub vos placo, "I entreat you"), from sub "under" (see sub-) + placare "to calm, appease, quiet, soothe, assuage," causative of placere "to please" (see please). In ancient Rome, a religious solemnity, especially in thanksgiving for a victory or in times of public danger.
"sacrament of the Lord's Supper, the Communion," mid-14c., from Old French eucariste, from Late Latin eucharistia, from Greek eukharistia "thanksgiving, gratitude," later "the Lord's Supper," from eukharistos "grateful," from eu "well" (see eu-) + stem of kharizesthai "show favor," from kharis "favor, grace," from PIE root *gher- (2) "to like, want." Eukharisteo is the usual verb for "to thank, to be thankful" in Septuagint and Greek New Testament. Related: Eucharistic.
mid-13c., "portable sanctuary carried by the Israelites in the wilderness," from Old French tabernacle "the Jewish Tabernacle; tent, canopy; tomb, monument" (12c.), from Latin tabernaculum "tent," especially "a tent of an augur" (for taking observations), diminutive of taberna "hut, cabin, booth" (see tavern).
Use of the word in English transferred late 14c. to the Temple in Jerusalem (which continued its function). Sense of "house of worship" first recorded 1690s. Also in Biblical language, "the body as the temporary abode of the soul" (late 14c.). The Old Testament Jewish Feast of Tabernacles (mid-October) was observed as a thanksgiving for harvest. This was rendered in English c. 1400 as Feste of Logges ("lodges"). Related: Tabernacular.
"sacred poem or song," especially one expressing praise and thanksgiving, Old English psealm (West Saxon sealm; Anglian salm), partly from Old French psaume, saume, and partly from Church Latin psalmus, from Greek psalmos "song sung to a harp," originally "performance on stringed instrument; a plucking of the harp" (compare psaltes "harper"), from psallein "play on a stringed instrument, pull, twitch" (see feel (v.)).
Used in Septuagint for Hebrew mizmor "song," especially the sort sung by David to the harp and collected in the Old Testament Book of Psalms. Related: Psalmodize. After some hesitation, the pedantic ps- spelling prevailed in English, as it has in many neighboring languages (German, French, etc.), but English is almost alone in not pronouncing the p-.