In the realm of education, summer can indeed refer to the break between the end of the spring term and the beginning of the fall term.
Those labels themselves should illustrate, however, that seasons in a particular context need not correspond to their astronomical or meteorological definitions. The spring semester, for example, typically begins in January— spring break may well come and go before the vernal equinox. A student who says I'm taking a Shakespeare course in the spring to another student will be understood to be referring to the academic term. If the same student said we're going to go camping in the spring, it is less clear without additional context whether she means the spring term or to the end of winter. A non-student would no doubt assume the latter.
- For institutions on the semester system (e.g. University of Texas at Austin), the spring term typically ends in early- to mid-May, and classes resume for the autumn in mid- to late August.
- For institutions on the quarter system (e.g. University of California, Los Angeles), the spring session typically ends in mid-June, with fall quarter classes beginning in late September.
- Institutions on the trimester system (e.g. Dartmouth College) have a similar calendar to the quarter system, but with an abbreviated summer session.
Summer is contextual in other seasonally-influenced fields as well. To meteorologists, it begins at the start of June, not with the solstice. For American workers, it is commonly the period between the Memorial Day holiday in late May to the Labor Day holiday in early September. And for the U.S. Department of Energy, it corresponds to the driving season which runs from April to September.