syringa /sɪˈɹɪŋ.ɡə/ noun3 •Any of the several flowering plants of the genus Philadelphus, such as now in the Western United States Philadelphus lewisii. •Any of the several flowering plants, of the genus Syringa, such as the lilacs. •(no longer used) Sweet mock orange (Philadelphus coronarius). formssyringas