Stum (?), n. [D. stom must, new wort, properly, dumb; cf. F. vin muet stum. Cf. Stammer, Stoom.] 1. Unfermented grape juice or wine, often used to raise fermentation in dead or vapid wines; must.

Let our wines, without mixture of stum, be all fine.
B. Jonson.

And with thy stum ferment their fainting cause.

2. Wine revived by new fermentation, reulting from the admixture of must. Hudibras.

Stum, v. t. [imp. & p. p. Stummed (?); p. pr. & vb. n. Stumming.] To renew, as wine, by mixing must with it and raising a new fermentation.

We stum our wines to renew their spirits.