WordWeb Online

1. By a factor of three
   - threefold, three times

1. Having more than one decidedly dissimilar aspects or qualities
   "a trifold role for an actor";
   - double, dual, twofold, two-fold, treble, threefold, three-fold
    
2. Three times as great or many
   "a claim for trifold damages";
   - treble, threefold, three-fold, triple

See also: multiple