viscount

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A nobleman ranking below an earl or count and above a baron.
2. n. Used as a title for such a nobleman.

Century Dictionary and Cyclopedia

1. n. Formerly, an officer who acted as deputy of a count or earl in the management of the affairs of the county; the sheriff of a county.
2. n. A degree or title of nobility next in rank below that of earl, and immediately above that of baron. It is the most recently established English title, having been first conferred by letters patent on John, sixth Baron Beaumont, by Henry VI., in 1440. In Great Britain the title is frequently attached to an earldom as a second title, and is by courtesy held by the eldest son during the lifetime of the father. The coronet of a viscount of England is composed of a circle of gold, chased, having on the edge twelve, fourteen, or sixteen pearls; the cap is of crimson velvet, turned up with ermine, and closed at the top with a rich tassel of gold. See cut under coronet.

Wiktionary

1. n. A member of the peerage above a baron but below a count or earl.

GNU Webster's 1913

1. n. (O. Eng. Law) An officer who formerly supplied the place of the count, or earl; the sheriff of the county.
2. n. engraving A nobleman of the fourth rank, next in order below an earl and next above a baron; also, his degree or title of nobility. See Peer, n., 3.

WordNet 3.0

1. n. a British peer who ranks below an earl and above a baron
2. n. (in various countries) a son or younger brother or a count