The answer is neuromuscular junction.
A contact between a neuron and a muscle fiber is called a neuromuscular junction. It is a chemical synapse. When an action potential reaches presynaptic terminal on a motor neuron, it will induce a release of neurotransmitters from the motor neuron. Neurotransmitters pass through the synaptic cleft and bind to the receptor on the muscle fiber. This results in muscle contraction.