An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) To have the same views, emotions, etc.; harmonize in opinion or feeling (often followed by with).
2) To give consent; assent (often followed by to).
3) To come to one opinion or mind; come to an arrangement or understanding; arrive at a settlement.
4) To be consistent; harmonize (usually followed by with).
5) To correspond; conform; resemble (Dictionary.com).

M.E. agre, agreen, from O.Fr. agreer "to receive with favor, take pleasure in," from phrase a gré "favorably, of good will," from L. → ad- "to" + gratum "pleasing," neuter of gratus "pleasing, agreeable," from PIE root *g^wer- "to praise;" cf. Pers. gerâmi "dear, revered," from Av. gar- "to praise;" Skt. grnati "sings, praises," Lith. giriu "to praise, celebrate."

Infinitive from sâcan, → agreement.

1) The act of agreeing or of coming to a mutual arrangement.
2) The state of being in accord (Dictionary.com).

Verbal noun from → agree + → -ment.

Sâcan, from sâz-, saz, sac-, sâj-, Pers. sâz-, sâxtan "to build, prepare; to agree, be compatible; to adapt, adjust;" sazidan "to suit, fit, be worthy," sazâ "suitable, agreeing with, congruous, deserving of;" Baluchi sâc-/sâcit "to adjust, be suitable, agree;" Mid.Pers. sacitan/sazidan "to fit," sazešn "fitness," sazâg "fitting, worth;" Av. sak- "to understand, to mark," sâcaya- (causative) "to teach;" Proto-Ir. *sac- "to fit, be suitable; to prepare;" + suffix -an, → minus.