If your little sister turns her lemonade stand into a lemonade empire, she might incorporate it as a company. Under the law, it would be considered an entity, or a separate being for purposes of government control.
The word entity originally meant "being, existence," and was borrowed from Medieval Latin entitas, from Latin ens, irregular form of esse "to be, exist." The suffix –ity means "quality or state." Medieval Christian philosophers, influenced by the Church Fathers and Aristotle, discussed the concept of ens "abstract being" versus esse "actual being."