think about (a fact, proposal, or request) deeply and at length

she began to mull over the various possibilities

they are mulling an overseas relocation

warm (an alcoholic drink, especially wine) and add sugar and spices to it

a saucepan on the stove works just fine since we don't mull the cider for very long

(of an alcoholic drink, especially wine) made into a hot drink with added sugar, spices, fruit, etc.

a glass of mulled wine