a comparatively young, irregularly shaped group of stars, often numbering up to several hundred, and held together by mutual gravitation; usually found along the central plane of the Milky Way and other galaxies.
a loose grouping of stars
A loose, irregular grouping of stars that originated from a single nebula in the arms of a spiral galaxy. Compared to globular clusters, open clusters generally contain younger and fewer (from a hundred to several thousand) stars and are confined to the disk of the galaxy. Because they are young, open clusters are sometimes still surrounded by the leftover gas and dust from which they formed. Visible from Earth with just a pair of binoculars and containing over 3,000 stars, the Pleiades is the best known open cluster. Also called galactic cluster. Compare globular cluster.
- Open-collar worker
job Someone who works at home or telecommutes. (1997-04-17)
- Open college
noun 1. the Open College, (in Britain) a college of art founded in 1987 for mature students studying foundation courses in arts and crafts by television programmes, written materials, and tutorials
- Open comedo
open comedo n. See blackhead.
noun, Ecclesiastical. 1. a communion service in which members of all denominations can participate.