An Etymological Dictionary of Astronomy and Astrophysics

Math.: Magnitude; quantity; a numerical quantity assigned to a mathematical symbol.

Etymology (EN): M.E., from O.Fr. value “worth, value,” noun use of feminine p.p. of valoir “be worth,” from L. valere “be strong, be well, be of value.”

Etymology (PE): Arzeš, verbal noun of arzidan “to be worth,” arzân “worthy; of small value, cheap,” arj “esteem, honour, price, worth;” Mid.Pers. arz “value, worth,” arzidan “be worth,”
arzân “valuable;” Av. arəjaiti “is worth,” arəja- “valuable,” arəg- “to be worth;” cf. Skt. arh- “to be worth, to earn,” árhant- “worthy person;” Gk. alphanein “to bring in as profit,” alphein “to ear, obtain;” Lith. algà “salary, pay;” PIE base *alg^wh- “to earn; price, value.”