- any of several small North American songbirds of the genus Sialia, having predominantly blue plumage, as the eastern S. sialis, which has a blue back and a reddish-brown breast.
- fairy bluebird.
- (usually initial capital letter) a member of Camp Fire, Inc., who is between the ages of six and eight.
- any North American songbird of the genus Sialia, having a blue or partly blue plumage: subfamily Turdinae (thrushes)
- fairy bluebird any songbird of the genus Irena, of S and SE Asia, having a blue-and-black plumage: family Irenidae
- any of various other birds having a blue plumage
also blue-bird, North American warbler-like bird, 1680s, from blue (1) in reference to its plumage + bird (n.1). Figurative use in bluebird of happiness is from 1909 play romance “l’Oiseau bleu,” literally “The Blue Bird,” by Belgian dramatist and poet Maurice Maeterlinck (1862-1949).