lilac

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various shrubs of the genus Syringa, especially S. vulgaris, widely cultivated for its clusters of fragrant purplish or white flowers.
2. n. A pale to light or moderate purple.

Century Dictionary and Cyclopedia

1. n. A shrub of the genus Syringa. See Syringa. The common lilacs are S. vulgaris and S. Persica, with their varieties; they abound, especially the former, as ornamental plants, cultivated for their beauty and fragrance. S.vulgaris is the larger species, having heart-shaped leaves and large thyrsiform clusters of purple flowers—the ordinary purple lilac or Scotch lilac, or, with white flowers, the common white lilac. There is also a blue-flowered variety. S. Persica, the Persian lilac, is a smaller, slender shrub, with looser panicles and pale flowers, blooming later, and also having a white variety. Countess Josika's lilac, S. Josikæa, discovered by the Countess von Josika in Transylvania, is a tall shrub with elliptical-lanceolate wrinkled leaves and bluish-purple scentless flowers. The Himalayan lilac, S. Emodi, is large, with dense panicles, but is not preferred to the common lilac. The lilac was formerly called pipe-tree or pipe-privets, and blue-pipe, on account of the large pith that could easily be bored out of the straight shoots to make pipe-stems. The common lilac has febrifugal properties. (See lilacine.) An oil is extracted from it for use in perfumery. The name lilac has also been given to various plants having some resemblance to the true lilac (see phrases below).
2. n. The color of the common lilac-blossom; a pale-purple color. A color-disk composed of one half artificial ultramarine, one sixth Chinese vermilion, and one third white will give a lilac.
3. Of the light-purple color of the flower of the common lilac.
4. n. A fanciers' name for a peculiar bluish-gray color shown in the coats of some domesticated mice.

Wiktionary

1. n. A large shrub of the genus Syringa, bearing white, pale pink or purple flowers.
2. n. Lilac flowers.
3. n. colour A pale purple colour, the colour of some lilac flowers.
4. adj. colour having a pale purple colour.

GNU Webster's 1913

1. n. (Bot.) 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.
2. n. A light purplish color like that of the flower of the purplish lilac.

WordNet 3.0

1. adj. of a pale purple color
2. n. any of various plants of the genus Syringa having large panicles of usually fragrant flowers