1911 Encyclopædia Britannica/Gill

GILL. (1) One of the branchiae which form the breathing apparatus of fishes and other animals that live in the water. The word is also applied to the branchiae of some kinds of worm and arachnids, and by transference to objects resembling the branchiae of fishes, such as the wattles of a fowl, or the radiating films on the under side of fungi. The word is of obscure origin. Danish has giaelle, and Swedish gäl with the same meaning. The root which appears in “yawn,” “chasm,” has been suggested. If this be correct, the word will be in origin the same as “gill,” often spelled “ghyll,” meaning a glen or ravine, common in northern English dialects and also in Kent and Surrey. The g in both these words is hard. (2) A liquid measure usually holding one-fourth of a pint. The word comes through the O. Fr. gelle, from Low Lat. gello or gillo, a measure for wine. It is thus connected with “gallon.” The g is soft. (3) An abbreviation of the feminine name Gillian, also often spelled Jill, as it is pronounced. Like Jack for a boy, with which it is often coupled, as in the nursery rhyme, it is used as a homely generic name for a girl.