Final answer:
The temporary complete cancellation of two overlapping waves that meet in precisely opposite phases is known as destructive interference. This follows the principle of superposition and is only temporary, with waves continuing unaffected thereafter.
Step-by-step explanation:
When two waves meet and only temporarily cancel each other out, this type of interference is known as destructive interference. However, as noted in your description, this cancellation is only temporary. When considering two simple pulses of the same amplitude moving toward one another in the same medium, as they overlap, at one point they may produce a resultant wave of zero amplitude—this is a moment of pure destructive interference when the waves are precisely out of phase, meaning one wave's crest aligns with the other's trough, causing them to cancel each other out. Afterward, they will continue on unaffected. This is in accordance with the principle of superposition, which states that the resultant wave at any point is the algebraic sum of the individual waves.