Which occurs when two or more waves combine to produce a wave with a larger displacement?

When two or more waves combine to produce a new wave, that's 'interference'.

-- If the new wave has larger displacements (amplitude), then it's CONstructive interference.

-- If the new wave has smaller displacements (amplitude), then it's DEstructive interference.

Due to constructive interference of two or more waves the net displacement is larger than the displacement of each wave.

Explanation:

When two or more waves superimpose at a point then the resultant displacement of medium particles is given by vector sum of displacement caused by each wave.

This phenomenon is known as superposition of waves and this is superposition of waves for coherent waves is known as interference.

Now in interference the net displacement is given by

here

= displacement due to each wave

= phase difference between two waves

now if it gives constructive interference then they two waves must be in same phase and hence the resultant displacement must be more than the individual wave