"situated near the ear," 1680s, from French parotide (1540s), or directly from Latin parotid-, stem of parotis, from Greek parotis "tumor near the ear," from para- "beside" (see para- (1)) + ot-, stem of ous "ear" (see ear (n.1)). As a noun, "the parotid gland." Middle English had parotide (n.) "a tumor or sore near an ear" (c. 1200).
"about, at or near (a given date)" when the exact time is unknown, 1856, from Latin circa (adv., prep.) "around, round about, near; in the region of; about the time of," alternative form of circum "round about" (see circum-).