E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Tace (2 syl.).
Latin for candle. Silence is most discreet. Tace is Latin for be silent, and candle is symbolical of light. The phrase means keep it dark, do not throw light upon it. Fielding, in his Amelia (chap. x.), says, Tace, madam, is Latin for candle. There is an historical allusion worth remembering. It was customary at one time to express disapprobation of a play or actor by throwing a candle on the stage, and when this was done the curtain was immediately drawn down. Oultor (vol. i. p. 6), in his History of the Theatres of London, gives us an instance of this which occurred January 25th, 1772, at Covent Garden theatre, when the piece before the public was An Hour Before Marriage. Someone threw a candle on the stage, and the curtain was dropped at once.
There are some auld stories that cannot be ripped up again with entire safety to all concerned. Tace is Latin for candle.Sir W. Scott: Redgauntlet, chap. xi. (Sir Walter is rather fond of the phrase.)
Mum, William, mum. Tace is Latin for candle.W. B. Yeats: Fairy Tales of the Irish Peasantry, p. 250.
N.B. We have several of these old phrases; one of the best is, Brandy is Latin for goose (q.v.).