"Unrealized" vs. "Realized" in Trading Explained

A question that has arisen several times is in regards to when money is 'actually made and/or lost in the market. Just because you buy a stock and it goes up does not mean you've officially made any money. On the flip side, just because a stock might go down after you buy doesn't mean you've officially lost money. There are a couple bits of terminology in the world of the stock market that explain this concept.