Lilac, the word itself describes

Lilac, the word itself describes the color as pale pinkish-violet colour.

Also refers to the ornamental flowers for garden. It blooms in spring season.

Other colours of lilac flower: white, violet, blue, magenta.

Van Gogh painted this artwork Lilacs in 1887. Now in Hammer Museum, Los Angeles.

Resource: Still life paintings by Vincent van Gogh (Paris)