An Etymological Dictionary of Astronomy and Astrophysics

A fourth of the Moon’s period or monthly revolution around Earth. → first quarter; → last quarter.

Etymology (EN): from O.Fr. quartier, from L. quartarius “fourth part,” from quartus “fourth,” related to quattuor “four,” cognate with Pers. câr, cahâr, as below.

Etymology (PE): Cârak “quarter,” literally “fourth, a fourth part of one,” from câr, contraction of cahâr, → four,

• -ak, contraction of yak, yek “one.” Yek “one, alone,” from Mid.Pers. êwak (Proto-Iranian *aiua-ka-); O.Pers. aiva- “one, alone;” Av. aēuua- “one, alone;” cf. Skt. éka- “one, alone, single;” Gk. oios “alone, lonely;” L. unus “one;” E. one.