The reabsorption of neurotransmitters by a terminal button is called:

The answer to this question would be reuptake

Reuptake is a reabsorption of the neurotransmitters that had been released. Reuptake is important because if the neurotransmitter isn't removed, they can repeatedly induce a signal.
Some drug works by inhibiting this reuptake mechanism like serotonin reuptake inhibitor. By doing this, the drug will increase the number of the neurotransmitter since it won't reabsorbed.