1. a splendid assemblage (especially of famous people)
2. tufted evergreen perennial herb having spikes of tiny white flowers and glossy green round to heart-shaped leaves that become coppery to maroon or purplish in fall
3. (astronomy) a collection of star systems; any of the billions of systems each having many stars and nebulae and dust;
"`extragalactic nebula' is a former name for `galaxy'"