Posset

n. [W. poset, curdled milk, posset, from pos, posiau, to gather, to heap. Cf. Lat. posca, an acidulous drink of mingled vinegar and water.] A beverage composed of milk curdled by some strong infusion, as by wine, &c., much in favor formerly. I have drugged their posset. Shak.

[imp. & p. p. POSSETED; p. pr. & vb. n. POSSETING.] To curdle; to turn, as milk with acids; as, to posset the blood. Shak.