TOS /tiː əʊ ɛs/verb 1noun 2phrase 1forms 4 verb1 •(Internet, old-fashioned) To report another user for a real or imagined terms of service violation. noun2 •Initialism of terms of service. •Initialism of thoracic outlet syndrome. phrase1 •(Commonwealth, historical) Initialism of taken on strength. formsTOS'd · TOSed · TOSing · TOSes