Seize On is a phrase that means to take advantage of an opportunity or situation. It is often used in the context of taking advantage of a moment to do something, such as seizing on a chance to make a difference or seize on an opportunity to make a profit. The term is also used to describe someone who is quick to act on an opportunity or situation. The crossword solution for Seize On is TAKEUP, which is a six-letter word meaning to take up or accept something.