semester (n.) Look up semester at Dictionary.com
1827, from German Semester "half-year course in a university," from Latin semestris, in cursus semestris "course of six months," from semestris, semenstris "of six months, lasting six months, half-yearly, semi-annual," from sex "six" (see six) + mensis "month" (see moon (n.)). Related: Semestral; semestrial.