Twenty in English is spelled "tw-e-n-t-y". It is an adjective that means being two more than eighteen or ten more than ten. For example, twenty dollars, twenty years old, and so on. When used as a noun, it refers to the number after nineteen and before twenty one. In mathematics, it is a cardinal number that follows nineteen and precedes twenty one. It can also be used to describe a group or collection of 20 individuals or items. For example, we can say "a class of twenty students".