YARN
Wool fibres spun into a thread.

YARN DYEING (SKEIN DYEING)
Dyeing yarn in skeins before knitting or weaving, usually in a solid shade.

YARN DYED FABRICS
Fabrics woven from yarns which have been dyed before the weaving process.

YIELD
The number of pounds of products at recognised moisture content obtained on processing an invoiced weight of 100kg of wool. It can be expressed in terms of washing yield, carbonised yield, Bradford top and noil yield, dry combing yield, etc.

YOLK
The combined secretion of the sebaceous and sudoriferous glands of the skin of the sheep. Grease or natural fat contained in raw or greasy wool.

YOLK STAIN
A stain caused by pigment from the yolk.

ZIBELINE
A woollen fabric, often striped, finished with ahighly napped surface of long, lustrous fibres pressed back to the cloth in one direction. used for coats and cloakings in women's wear.

ZYGOTE
The fertilised egg following the union of the spermatzoon with the ovum.