cedar UK /ˈsiː.də/US /ˈsi.dɚ/ noun4 •A coniferous tree of the genus Cedrus in the family Pinaceae. •A coniferous tree of the family Cupressaceae, especially of the genera Juniperus, Cupressus, Calocedrus, or Thuja.There had been dry seasons, accumulations of dust, wind-blown seeds, and cedars rose wonderfully out of solid rock. — 1912 •A flowering tree of the family Meliaceae, especially of the genera Cedrela or Toona. •The aromatic wood from a tree of genus Cedrus or from any of several not closely related trees. formscedars