A semester is specifically half of the academic year, usually about six months, as in the spring semester. A term is a more general word for any fixed block of the school calendar, whether that calendar is split into two semesters or three shorter terms. Think of semester as one particular way of carving up the year, and term as the wider label that covers all the ways of doing it.
The core difference
Semester names one specific two-part academic calendar; term is the general word for any study period, and also covers meanings well beyond education.
- semester — half of an academic year, roughly six months: She's studying abroad for the spring semester.
- term — a fixed period dividing an academic year (or a period in office): School starts again for the new term in September.
- term — also a word with a specific meaning in a field, or the conditions of an agreement: "Bull market" is a term used a lot in finance.
How to tell them apart
The simplest test is arithmetic: if a school year is split into two blocks, those blocks are semesters. If it is split into three, they are usually called terms rather than semesters, because a semester specifically means a half. Once you remember that semester is built from a word meaning six, the two-part structure is easy to recall.
Term does far more work outside the classroom. It can mean a word or phrase with a precise meaning, the conditions in a contract, or a spell in office, none of which semester can do. So while every semester is a kind of term, most uses of term have nothing to do with semesters at all.
