E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
In some rural districts the custom still prevails of Thomasingthat is, of collecting small sums of money or obtaining drink from the employers of labour on the 21st of DecemberSt. Thomass Day. December 21st is still noted in London as that day when every one of the Common Council has to be either elected or reelected, and the electors are wholly without restriction except as to age and sex. The aldermen and their officers are not elected on St. Thomass Day.