yolk

views updated May 09 2018

yolk / yōk/ • n. the yellow internal part of a bird's egg, which is surrounded by the white, is rich in protein and fat, and nourishes the developing embryo. ∎ Zool. the corresponding part in the ovum or larva of all egg-laying vertebrates and many invertebrates.ORIGIN: Old English geol(o)ca, from geolu ‘yellow.’

The Oxford Pocket Dictionary of Current English

yolk

views updated May 29 2018

yolk Material, consisting of a mixture of lipids and proteins, secreted in the form of granules, that in eggs act as a source of food for the growth and development of an embryo.

A Dictionary of Zoology MICHAEL ALLABY

yolk

views updated Jun 27 2018

yolk The food stored in an egg for the use of the embryo. It can consist mainly of protein (protein yolk) or of phospholipids and fats (fatty yolk). The eggs of oviparous animals (e.g. birds) contain a relatively large yolk.

A Dictionary of Biology

yolk

views updated Jun 11 2018

yolk2 greasy substance of sheep's skin glands. XVII. repr. OE. *eowoca, in the adj. eowociġ; see -Y1.

The Concise Oxford Dictionary of English Etymology T. F. HOAD

yolk

views updated May 18 2018

yolk Rich substance found in the eggs or ova of most animals except those of placental mammals. It consists of fats and proteins and serves as a store of food for the developing embryo.

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