Definition of "zun"

Zome woys avore the zun is down,So long’s the sky is clear;

1850, James Orchard Halliwell, A Dictionary of Archaic and Provincial Words, Obsolete Phrases, Proverbs, and Ancient Customs, from the Fourteenth Century

GOOD bwye ta thee Cot! whaur tha dâs o’ my childhoodGlaw’d bright as tha zun in a mornin o’ mâ;

1869, James Jennings, The Dialect of the West of England, particularly Somersetshire