[thriftwy]

You can divide year into halves, thirds and quarters. You do not have to negotiate boundaries every time.

[scotty79]

It's funny how rarely thirds of a year come up. I can't recall a single thing for which they are used

[skissane]

Some universities divide the academic year into two semesters, others divide it into three trimesters. It also sometimes happens that, within the same university, some programs use one and others use the other-at my alma mater, only a minority of graduate programs used trimesters, every else was semesters.