late 14c., "organized association of persons invested with certain powers and rights or engaged in some common duty or pursuit," especially "body of scholars and students within an endowed institution of learning," also "resident body of ecclesiastics supported by an endowment," from Old French college "collegiate body" (14c.) and directly from Latin collegium "community, society, guild," literally "association of collegae," plural of collega "partner in office," from assimilated form of com "with, together" (see com-) + leg-, stem of legare "to choose," from PIE root *leg- (1) "to collect, gather."
At first, any corporate group (the general sense is preserved in U.S. electoral college, the Vatican's college of cardinals, etc.). In the academic sense, colleges operated within universities (as still at Oxford and Cambridge), but in Scotland, and later in U.S. and Canada some universities had only one college, and there college came to be used for "incorporated and endowed institution of learning of the highest grade," and eventually "any degree-giving educational institution" (c. 1800). College-widow is attested by 1878.