Olive pomace oil is olive oil that is extracted from the olive pulp after the first press.
Once the mechanical oil extraction of olive oil is complete, approximately 5-8% of the oil remains in the pulp, which then needs to be extracted with the help of solvents which is  an industrial technique used in the production of most other edible oils.
Although the oil extracted in this manner is still olive oil, at retail it may not simply be called “olive oil”.