1) An aphetic spelling of abate, that is to lower the value or price.
1544 salvinge that my wif shall bate xls for a childe borde iij yeres, Gildersome
1545 payd ... for the lodyng of the sayd tymbre ... one peny bated in the hole [whole], Bridlington.
2) A word used in a pre-tannage process which made the skins softer.
They were immersed in a solution which is described in an account of tanning in Beverley as ‘a paste made from the dung of animals, especially dogs and chickens’. This mixture contained ‘concentrations of enzymes … which digested the fibre-like proteins in the hides’ to help make them more supple. It was an alkaline solution and it neutralized the effect of the previous application of lime. The OED examples are late: 1804 A Tan-Yard, containing … securing-tubs, and bates, Hull, but the word has a long history in Yorkshire: 1660 6 stick lethers in the baite 8s, Selby and was still in use in nineteenth-century documents for Whitley near Mirfield.