- Firth, J. R. Firth, John Rupert Firth - English linguist who contributed to linguistic semantics and to prosodic phonology and who was noted for his insistence on studying both sound and meaning in context (1890-1960)
--1 is a kind of linguist, linguistic scientist
- firth - a long narrow estuary (especially in Scotland)
--2 is a kind of estuary
--2 has particulars: Firth of Clyde; Firth of Forth; Moray Firth; Solway Firth