consent (n.) Look up consent at Dictionary.com
c. 1300, "approval," also "agreement in sentiment, harmony," from Old French consente, from consentir (see consent (v.)). Age of consent is attested from 1809.
consent (v.) Look up consent at Dictionary.com
early 13c., from Old French consentir (12c.) "agree, comply," from Latin consentire "feel together," from com- "with" (see com-) + sentire "to feel" (see sense (n.)). "Feeling together," hence, "agreeing, giving permission," apparently a sense evolution that took place in French before the word reached English. Related: Consented; consenting.