overstream UK /əʊvəˈstɹiːm/US /oʊ.vɚˈstɹim/noun 1verb 1forms 3 noun1 •(rare) An excessive, steady flow, succession of something.I must have a definite mark by which to locate him in that rugged territory overstream. — 1942 verb1 •To stream or flow over. formsoverstreamed · overstreaming · overstreams