any of various plants (esp. of the genera Campanula and Mertensia of the bellflower and borage families) with blue, bell-shaped flowers, as the harebell or Virginia bluebell
See bluebell in American Heritage Dictionary 4
(blo͞oˈbĕlˌ) also blue·bells(-bĕlzˌ)
noun
Any of several bulbous plants of the genus Hyacinthoides (syn. Endymion) in the lily family, native to western Europe and northwest Africa and having racemes of usually blue to pink bell-shaped flowers. Also called wood hyacinth.
Any of numerous plants of the genus Mertensia, native to Asia, Europe, and North America and having blue, trumpet-shaped flowers.