All amphiprotic substances are amphoteric, but not all amphoteric substances are amphiprotic.
Amphoteric substances can act as both an acid and a base, but as you know there are many ways a substance can do this (protons, electron pairs...)
Amphprotic substances are a sub-branch of amphoterism, and are substances that can donate or recieve a proton (H+) acting as both an acid and a base.
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