1) Arm 2) Bay 3) Gulf 4) Inlet 1) JR firth 2) Actor Colin 3) Coastal and oceanic landform 4) Estuary 5) John rupert firth 6) Linguist 7) Linguistic scientist 8) Long, narrow estuary 9) Narrow arm of the sea 10) Scottish boy name 11) Scottish estuary 12) Scottish inlet 
Firth is the word in the Lowland Scots language and in English used to denote various coastal waters in Scotland and England. In mainland Scotland it is used to describe a large sea bay, or even a strait. In the Northern Isles it more usually refers to a smaller inlet. It is linguistically cognate to fjord (both from Proto-Germanic *ferþuz) which...
• (n.) An arm of the sea; a frith.
estuary
Meaning as a surname: Living on or near scrubland.
Firth noun [ Scot. See Frith .] (geog.) An arm of the sea; a frith. 
Firth is the Scottish name for a narrow arm of the sea, usually the outlet of a river. The English equivalent, frifth is a result of simple translation.
Derived from Old Icelandic fjǫrdic (see fjord)
[n] - 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) 2. [n] - a long narrow estuary (especially in Scotland)
a long, narrow indentation of the seacoast.