The pot frothed, or raised a scum, when about to boil. (S, K.)
2.
-A2- كَرْفَأَ, verbal noun كَرْفَأَةٌ; and ↓تكرفأ; (like كرثأ and تكرثأ, K, which are said to be changed from the former; TA;) It (a collection of clouds) became large in quantity, and confused, and heaped up. (K.)