Firth is a word in the
Scots and
English languages used to denote various coastal waters in
Scotland and
England. In mainland Scotland, it is used to refer to 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 has a more constrained sense in English. Bodies of water named "firths" tend to be more common on the east coast, or in the southwest of the country, although the
Firth of Lorn is an exception to this. The
Highland coast contains numerous estuaries, straits, and inlets of a similar kind, but not called "firth" (e.g.
the Minch and
Loch Torridon); instead, these are often called
sea lochs.