The word is a modern English compound adjective formed by directly combining the numeral "two" with the noun "semester." "Two" originates from the Proto-Indo-European root dwo-, which is the source for the number across many Indo-European languages. "Semester" has a more specific academic lineage, entering English via German 'Semester' from Latin 'semestris', literally meaning a period of six months. The compound "two-semester" logically describes anything—typically a course or program—that spans the duration of two such academic periods, illustrating a straightforward and transparent method of term formation in English.

Structure: two (number) + semester (academic term) - two: From Old English 'twā', meaning the number 2. In this compound, it functions as a numerical quantifier. - semester: From Latin 'semestris', meaning 'of six months', from 'sex' (six) + 'mensis' (month). In this compound, it functions as the noun being quantified.