lilac, n. [Sp. lilac, lila, Ar. līlak, fr. Per. līlaj, līlanj, līlang, nīlaj, nīl, the indigo plant, or from the kindred līlak bluish, the flowers being named from the color. Cf. Anil.].
A shrub of the genus Syringa. There are six species, natives of Europe and Asia. Syringa vulgaris, the common lilac, and Syringa Persica, the Persian lilac, are frequently cultivated for the fragrance and beauty of their purplish or white flowers. In the British colonies various other shrubs have this name. [1913 Webster]
A light purplish color like that of the flower of the purplish lilac. [1913 Webster]
California lilac(Bot.), a low shrub with dense clusters of purplish flowers (Ceanothus thyrsiflorus).
lilac, n. & adj.
--n.
1 any shrub or small tree of the genus Syringa, esp. S. vulgaris with fragrant pale pinkish-violet or white blossoms.
2 a pale pinkish-violet colour.
--adj. of this colour.
Etymology
obs. F f. Sp. f. Arab. lilak f. Pers. lilak, var. of nilak bluish f. nil blue