From Hull AWE
- In Biology, the gill (pronounced with a hard '-g-', like that in 'get' or 'girl', IPA: /gɪl/) is the equivalent in fish, and other aquatic animals, of the lung in mammals: the organ with which it obtains oxygen from the surrounding fluid (water for fish and air for mammals). There is a structure superficially resembling this, but in fact a reproductive structure, in mushrooms.
- In geography, the element gill, pronounced in the same way, (sometimes spelled gyll) means 'a ravine' (a narrow rocky valley) or the stream or small river which has formed it. The word, of Old Norse origin, is most common in the north of England, and is best left to dialect except where it forms part of a recognized proper noun. In this case, spell it as the Ordnance Survey, or a good place-name Dictionary, records it. (OED notes "The spelling ghyll, often used in guide-books to the Lake district, seems to have been introduced by Wordsworth [(1770-1850)]"; but if that is the spelling recognized by the authorities, use it.)
- A gill (soft 'g', IPA: /dʒɪl/) is a unit of measurement in the imperial system and, with a rather different definition, in the USA. (Wikipedia has a clear statement of the difference, [].) It is a quarter of a pint, in the UK - and obsolete, except in so far as pubs serve spirits in fractions of a gill, 1/6 gill (23.7 ml) in England, and 1/5 gill (28.4 ml) in Scotland.
- A gill, sometimes spelled jill and pronounced similarly with a soft 'g', is the name for a female of certain species in the mustelidase genus - notably ferrets, polecats and weasels. The equivalent name for a male is 'hob'. It has also been applied to mares (female horses), and - like so many words in our sexist past - as "A familiar or contemptuous term applied to a woman; a lass, wench" OED. (This usage is ascribed by The Concise Oxford Dictionary of English Etymology [] to the shortening of Gillian.)
- Two proper nouns are also worth attention: