Oosquai is a particularly potent alcoholic drink made and consumed by the Aiel. Made from zemai, (corn) it looks "like faintly brown-tinged water, tasted almost like it — and was stronger than double-distilled brandy" according to Rand al'Thor.
The sharing of oosquai with another person is said to be a great act of friendship between warriors.
In our world, we would call it whiskey. This is supported by the word zemai reading as maize (or corn) with the phonemes reversed; corn is one of the grains that can be used to make whiskey.