Mass
late Middle English: from Old French masse, from Latin massa, from Greek maza ‘barley cake’; perhaps related to massein ‘knead’.
wiktionary
In late Middle English (circa 1400) as masse in the sense of "lump, quantity of matter", from Anglo-Norman masse, in Old French attested from the 11th century, via late Latin massa(“lump, dough”), from Ancient Greek μᾶζα(mâza, “barley-cake, lump (of dough)”). The Greek noun is derived from the verb μάσσω(mássō, “to knead”), ultimately from a Proto-Indo-European *maǵ-(“to oil, knead”). Doublet of masa. The sense of "a large number or quantity" arises circa 1580. The scientific sense is from 1687 (as Latin massa) in the works of Isaac Newton, with the first English use (as mass) occurring in 1704.
From Middle English messe, masse, from Old English mæsse(“the mass, church festival”) and Old French messe, from Vulgar Latin *messa(“Eucharist, dismissal”), from Late Latin missa, noun use of feminine past participle of classical Latin mittere(“to send”), from ite, missa est(“go, (the assembly) is dismissed”), reanalyzed as "go, [that] is the missa", last words of the Roman Rite of the Catholic Church. Compare Dutch mis(“mass”), German Messe(“mass”), Danish messe(“mass”), Swedish mässa(“mass; expo”), Icelandic messa(“mass”). More at mission.
etymonline
mass (n.1)
late 14c., "irregular shaped lump; body of unshaped, coherent matter," from Old French masse "lump, heap, pile; crowd, large amount; ingot, bar" (11c.), and directly from Latin massa "kneaded dough, lump, that which adheres together like dough," probably from Greek maza "barley cake, lump, mass, ball," which is related to massein "to knead," from PIE root *mag- "to knead, fashion, fit."
The sense in English was extended 1580s to "a large quantity, amount, or number." Meaning "bulk" in general is from c. 1600. As "the bulk or greater part of anything" from 1620s. Strict sense in physics, "quantity of a portion of matter expressed in pounds or grams" is from 1704.
As an adjective, "of, involving, or composed of masses of people; done on a large scale," from 1733, first attested in American English mass meeting "public assembly persons in mass or of all classes to consider or listen to the discussion of some matter of common interest." Mass culture is from 1916 in sociology (earlier in biology); mass hysteria is from 1914; mass movement is from 1897; mass grave is from 1918; mass murder from 1880.
mass (n.2)
"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.
mass (v.)
late 14c., transitive, "to form into a mass" (implied in y-maced), from mass (n.1) or from French masser. Intransitive sense of "to gather in a mass, collect in masses" is by 1560s. Related: Massed; massing.
