"act or fact of sharing or partaking in common with another or others; act or state of receiving or having a part of something," late 14c., participacioun, from Old French participacion (13c.) and directly from Late Latin participationem (nominative participatio) "partaking," noun of action from past-participle stem of Latin participare "participate in, share in, partake of; to make partaker, to share, impart," from particeps (genitive participis) "partaker, comrade, fellow soldier," also, as an adjective, "sharing, partaking," from pars (genitive partis) "a part, piece, a division" (from PIE root *pere- (2) "to grant, allot") + -cip-, weak form of stem of capere "to take," from PIE root *kap- "to grasp." Related: Participational "involving or requiring participation" (1952).

"short, quick, forward and downward motion of the head," voluntary or not, 1530s, from nod (v.).

c. 1600, "one who offers himself for military service," from French voluntaire, "one who volunteers," also as an adjective, "voluntary," from Latin voluntarius "voluntary, of one's free will," as a plural noun "volunteers" (see voluntary). Non-military sense is first recorded 1630s. As an adjective from 1640s. Tennessee has been the Volunteer State since the Mexican War, when a call for 2,800 volunteers brought out 30,000 men.

late 14c., communioun, "participation in something; that which is common to all; union in religious worship, doctrine, or discipline," from Old French comunion "community, communion" (12c.), from Latin communionem (nominative communio) "fellowship, mutual participation, a sharing," used in Late Latin ecclesiastical language for "participation in the sacrament," from communis "common, general" (see common (adj.)).

Used by Augustine, in belief that the word was derived from com- "with, together" + unus "oneness, union." In English, from mid-15c. as "the sacrament of the Eucharist," from c. 1500 as "act of partaking in the sacrament of the Eucharist." From 1610s as "intercourse between two or more."

"one who participates, a partaker," 1560s, from French participant, from Latin participantem (nominative participans), present participle of participare "to share in, partake of" from particeps "sharing, partaking" (see participation).

1580s, from French initiation or directly from Latin initiationem (nominative initiatio) "participation in secret rites," noun of action from past-participle stem of initiare "originate, initiate," from initium "a beginning" (see initial (adj.)).