From Traderpedia

Definition: A term used to describe a single, completed trade - one that has been opened and then closed or offset.

A trader who does 100 roundtrips has opened and closed 100 contracts worth of trades. This could be either as one position of 100 contracts, or 100 individual trades - the term "roundtrips" refers to the number of opened and closed, completed contracts.

[edit] See also

• round-turn