This is also known as conditioned reinforcement in operant conditioning. Secondary Reinforcement refers to a situation wherein a stimulus reinforces a behavior after being previously associated with a primary reinforcer or a stimulus that satisfies basic survival instinct such as food, drinks, and clothing. A secondary reinforcer can be helpful or not.
Let's look at a well known example - Money. Money is a secondary reinforcer because it doesn't directly reinforce you--money itself doesn't make you less hungry, less thirsty, etc--but you can use the money to get food, water, and other primary reinforcers. Therefore, you get secondary reinforcement through the ability to use money to get primary reinforces.
Think of it this way, If you were stuck on a deserted island, a secondary reinforcer like money can't help you stay alive, right?