what does fault lines mean
â¢ FAULT LINE (noun). The noun FAULT LINE has 1 sense: 1. (geology) line determined by the intersection of a geological fault and the earth's surface. Familiarity information: FAULT LINE used as a noun is very rare. FAULT LINE (noun). The noun FAULT LINE has 1 sense: 1. (geology) line determined by the intersection of a geological fault and the earth's surface. Familiarity information: FAULT LINE used as a noun is very rare.