communicant (n.)

early 15c., "act of communicating, act of imparting, discussing, debating, conferring," from Old French comunicacion (14c., Modern French communication) and directly from Latin communicationem (nominative communicatio) "a making common, imparting, communicating; a figure of speech," noun of action from past-participle stem of communicare "to share, divide out; communicate, impart, inform; join, unite, participate in," literally "to make common," related to communis "common, public, general" (see common (adj.)). Meaning "that which is communicated" is from late 15c.; meaning "means of communication" is from 1715. Related: Communications; communicational.

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 does not receive the holy communion," c. 1600, from non- + communicant.