lilac (n.) Look up lilac at
1620s, shrub of genus Syringa with mauve flowers, from French lilac, from Spanish lilac, from Arabic lilak, from Persian lilak, variant of nilak "bluish," from nil "indigo" (compare Sanskrit nilah "dark blue"), a word of uncertain origin. Attested from 1791 as a color name; as a scent, from 1895. As an adjective, "pale pinkish-purple," from 1801. Related: Lilaceous.