[L. tacē, imper. of tacēre to be silent.] The Latin for ‘Be silent.’ Tace is Latin for a candle, a humorously veiled hint to any one to keep silent about something.
[Cf. 1605. Camden, Rem., 162 (Impresses). Edmund of Langley … asked his sonnes … what was Latine for a fetter-locke: Whereat when the yong gentleman studied, the father said, ‘… I will tell you, Hic hæc hoc taccatis,’ as advising them to be silent and quiet.]
1697. Dampier’s Voy., 356. Trust none of them for they are all Thieves, but Tace is Latin for a Candle.
1752. Fielding, Amelia, I. x. ‘Tace, Madam,’ answered Murphy, ‘is Latin for a candle; I commend your prudence.’
1821. Scott, Fam. Lett., 24 Feb. (1894), II. 115. Tace shall be hereafter with me ‘Latin for a candle.’
