The term "buoyancy" refers to the upward force placed on an object when placed in fluid. This force isn't always enough to make an object float, so there are three states of buoyancy.

Objects that are less dense than a fluid will float because they displace an amount of water that weighs more than the object.

Objects that are denser than a fluid will sink because the fluid displaced weighs less than the object.

Neutrally buoyant objects neither float nor sink. Instead, they hover in the water. In order to be neutrally buoyant, an object must have the same density as the fluid it's placed in.