The idea of a semester originated in German universities, with English adopting the term in 1826. Its roots can be traced back to the Latin word semestris, meaning “of six months” (although the German system is typically six months long, while many American colleges now have semesters of around five months). The term semestris is a combination of two Latin words: sex, which means “six”, and mensis, which means “month”. Similarly, the term trimester translates to “three months” and is used in pregnancy and academic contexts (even if the academic term is not always three months in duration). The root of sex comes from the Proto-Indo-European root sweks, also signifying “six”, while mensis likely traces back to the Proto-Indo-European word for “moon” and is related to the concept of measurement.
