1. Literally, the highest possible score or mark that one can achieve on a given exam, test, assignment, or course of study. All her hard work paid off when she received full marks on her final exam.

2. By extension, full and proper credit or praise for someone's action, remark, or achievement. Typically followed by the prepositions "to" or "for." Primarily heard in UK. Full marks to Joanna for her outstanding work on the merger. Though they lost, you've got to give the team full marks for their tremendous effort.