the time during which a school holds classes; "they had to shorten the school term"
is ‘owned' by terms; for instance, the Spring term has within it the Spring, July, August and Summer sessions. Sessions may overlap but terms may not.
The fall/winter period from September through April or the spring/summer session from May to August. Both sessions are composed of two terms. Full-credit courses generally run for a complete session while most half-credit courses are for a single term only.
An academic session is one of three semesters called: Spring, Fall, Winter.
The university year is divided into the Regular Session, with classes from September to April, and the Summer Session with classes from May to mid-August. All sessions are divided into two terms, with each term including an examination period.
A time period during which classes are scheduled within an academic term. (Depending on the department, sometimes the session is the same period as the term.)