The phrase 'Mind the GAP' is a warning used in many public transportation systems, such as the London Underground, to remind passengers to be careful when crossing the GAP between the train and the platform. The crossword solutions for this phrase are GAP (3 letters) and STORE (5 letters). GAP is an acronym for 'Gulf Atlantic Pipeline, ' which is a company that operates a network of pipelines in the United States. STORE is an acronym for 'Strategic Oil Reserve, ' which is a government-owned stockpile of oil reserves located in the United States.