member (n.)

late 13c., "sex organ" (compare Latin membrum virile, but in English originally of women as well as men), also, "body part or organ" (in plural, "the body"), from Old French membre "part, portion; topic, subject; limb, member of the body; member" (of a group, etc.)," 11c., from Latin membrum "limb, member of the body, part," probably from PIE *mems-ro, from root *mems- "flesh, meat" (source also of Sanskrit mamsam "flesh;" Greek meninx "membrane," mēros "thigh" (the "fleshy part"); Gothic mimz "flesh"). In English, sense of "person belonging to a group" is first attested early 14c., from notion of "constituent part of a complex structure." Meaning "one who has been elected to parliament" is from early 15c.