An in-the-money option is an option that would be worth something if it were exercised now, one of the states of moneyness set out in the main entry on in-the-money and out-of-the-money options. A call is in the money when the underlying trades above the strike price, and a put is in the money when the underlying trades below it. With a share at 108, a call struck at 100 is in the money by 8, and a put struck at 115 is in the money by 7.
That amount is the option's intrinsic value, and the premium of an in-the-money option is made up of it plus a smaller amount of time value. The deeper in the money an option is, the more its price moves one-for-one with the underlying, so its delta approaches 1 for a call and minus 1 for a put.
Being in the money does not mean the holder has made a profit, since the premium paid may exceed the intrinsic value. Options that are in the money at option expiry are normally exercised automatically, while an out-of-the-money option expires worthless.