Many of the traditional Christmas songs in English contain words or references that have changed in meaning or fallen out of common use.
The familiar “Deck the Halls with Boughs of Holly” (words from 1881), has several words that may stump native and non-native speakers alike.
Deck in the title is a verb meaning “adorn.” It entered the language in about 1570; from Middle Dutch dekken “to cover.”
Don we now our gay apparel…
The verb don, meaning “put on,” is a 14th century contraction of “do on.” Ex. Do on your shoes. The word doff, “take off” is a contraction of “do off.” Doff your hat in the house. Gay entered the language in the 12th century with the meaning “full of joy or mirth.” According the the Online Etymology Dictionary,
The word gay in the 1890s had an overall tinge of promiscuity — a gay house was a brothel. The suggestion of immorality in the word can be traced back to 1637. The “Dictionary of American Slang” reports that gay (adj.) was used by homosexuals, among themselves, in this sense since at least 1920. Gay as a noun meaning “a (usually male) homosexual” is attested from 1971.
Troll the ancient Yuletide carols…
troll (v) “to sing in a full, rolling voice;” c. 1575. The word derives for a hunting term meaning “to look for game in a wandering fashion.” Yuletide is used now as a synonym for the Christmas season in general. In a more narrow sense it can refer to the “12 days of Christmas,” usually counted from Christmas on December 25 to the arrival of the Three Kings on January 6 (Epiphany). Before the arrival of Christianity, Germanic pagans, including the ancestors of English Christians, celebrated the Winter Solstice as Yule. The Yule log represented the renewal of the sun. The suffix –tide in Yuletide is from O.E. tid,”point or portion of time, due time,” The tide that ebbs and flows is from the same word. When the word carol entered English about 1300, it referred to a dance. The meaning of carol as “Christmas hymn” dates from 1502. Could be there was singing along with the dancing and the dancing part dropped out.
You can read some curious facts about four traditional carols here.