What it is:
The phrase call over is used to describe the exercising of a call option.
How it works (Example):
A call option gives its owner the right to buy an asset at a set price (the strike price) on or before a certain day (the expiration date). If you own a call option on 100 shares of Company ABC stock with a strike price of $25 per share, you will call over the shares of stock once the stock price exceeds $25.