early 12c., sancte Martines mæsse, the church festival formerly held on Nov. 11 in honor of the patron saint of France, St. Martin, late 4c. bishop of Tours noted for destroying the remaining heathen altars. Also see mass (n.2).
kind of swallow-like bird (Chelidon urbica), 1580s (earlier in diminutive form maretinet, mid-15c.), from Old French martin, which is apparently from the masc. proper name Martin in some sense. Writers in 17c. said it was named for St. Martin of Tours (d. 397 C.E.), patron saint of France, whose festival day (Martinmas) is Nov. 11, about the time the birds are said to depart for winter. But OED says the naming "may have been purely arbitrary," and Century Dictionary says "the name has no specific meaning ...." Usually with a qualifying term: the common house-martin is so called because it nests under the eaves of houses. The American purple martin is so called by 1804.
"eucharistic service," Middle English messe, masse, from Old English mæsse, from Vulgar Latin *messa "eucharistic service," literally "dismissal," from Late Latin missa "dismissal," fem. past participle of mittere "to let go, send" (see mission).
Probably so called from the concluding words of the service, Ite, missa est, "Go, (the prayer) has been sent," or "Go, it is the dismissal." The Latin word sometimes was glossed in Old English as sendnes "send-ness." Meaning "musical setting of certain parts of the Catholic (or Anglican) liturgy" is by 1590s.
<a href="https://www.etymonline.com/word/Martinmas">Etymology of Martinmas by etymonline</a>
Harper, D. (n.d.). Etymology of Martinmas. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/Martinmas