breaststroke /ˈbɹɛstˌstɹoʊk/noun 1verb 1forms 3 noun1 •A swimming stroke in which the swimmer lies face down, the arms being swept forward, outward and back under the water and the legs are kicked like a frog's verb1 •To swim using this stroke. formsbreaststroked · breaststroking · breaststrokes