combination

1. Accounting: Amalgamation of two or more distinct firms into a single accounting entity.

2. Mathematics: Arrangement in which the order or sequence of the items comprising a group is unimportant. In contrast, permutation is an arrangement where their order or sequence is critically important.

3. Options trading: Arrangement involving two long positions (a long call and a long put) or two short positions (a short call and a short put) with different expiration dates and exercise prices.