tau·tol·o·gy n. pl. tau·tol·o·gies
Needless repetition of the same sense in different words; redundancy.
An instance of such repetition.
Logic. An empty or vacuous statement composed of simpler statements in a fashion that makes it logically true whether the simpler statements are factually true or false; for example, the statement Either it will rain tomorrow or it will not rain tomorrow.
If I'm not careful and I hit refresh too many times, my posts will become tautologic.