imaginary UK /ɪˈmæd͡ʒɪnəɹi/US /ɪˈmæd͡ʒɪˌn(ɛ)ɹi/adjective 3noun 3forms 3 adjective3 •Existing only in the imagination.Unicorns are imaginary. •Relating or belonging to the imagination.Fiction refers to imaginary stories. — 2003 •Having no real part; that part of a complex number which is a multiple of √ (called imaginary unit). noun3 •Imagination; fancy. •The set of values, institutions, laws, and symbols common to a particular social group and the corresponding society through which people imagine their social whole. •An imaginary number. formsimaginaries · more imaginary · most imaginary