n. [ L. ] (Bot.) A small leguminous tree (Cytisus Laburnum), native of the Alps. The plant is reputed to be poisonous, esp. the bark and seeds. It has handsome racemes of yellow blossoms. [ 1913 Webster ]
☞ Scotch laburnum (Cytisus alpinus) is similar, but has smooth leaves; purple laburnum is Cytisus purpureus. [ 1913 Webster ]