1. To wait or pause for a moment. Often used as an imperative. Can you please wait a second so I can tie my shoe? We waited a second before turning the water back on.

2. A phrase spoken when one has a realization about something they had not thought of until that moment. Wait a second, Jeff said he was driving here, but his car is in the shop. He must have forgotten. Wait a second... these aren't bananas, they're plantains!