What is the meaning of Oon?

An oven.

Thomas Darlington (1887) The Folk-speech of South Cheshire, page 225

first-person singular present indicative of olla

genitive singular of oo

first-person singular indicative present of olla

Alternative form of on (one)

Alternative form of on (one)

Alternative form of on (singly)

avocado

Source: wiktionary.org