a·gree / əˈgrē/ • v. (a·grees, a·greed, a·gree·ing) [intr.] 1. have the same opinion about something; concur: I completely agree with your editorial [tr.] the authors agree that Jerusalem must remain united. ∎  (agree with) approve of (something) with regard to its moral correctness: I'm not sure I agree with abortion.2. (agree to or to do something) consent to do something that has been suggested by another person: she had agreed to see a movie with him. ∎  [intr.] reach agreement about (something), typically after a period of negotiation: the commission agreed on a proposal.3. (agree with) be consistent with: your body language does not agree with what you are saying. ∎  Gram. have the same number, gender, case, or person as: make the verb agree with the subject. ∎  be healthy or appropriate for someone: she's eaten something that did not agree with her.PHRASES: agree to differsee differ.

agree †please; become favourable, accede XIV; be in harmony or accord XVI. — (O)F. agréer :- Rom. *aggrātāre, f. L. AG- + grātus pleasing (cf. GRACE).
So agreeable (hence agreeably), agreement XIV.

AGREE (əˈgriː) Advisory Group on Reliability of Electronic Equipment