fɔː fɔɹ fo(ː)ɹ ˈkwɒdɹʊpl kwɑˈdɹupəl kwɔː(ɹ)ˈtɛt ˈkwɑːtɚˌnɛəɹi kwəˈtəːni.ən ˈtɛtɹæd a set of four similar things considered as a unit one of four children born at the same time from the same pregnancy the cardinal number that is the sum of three and one