So far as I know, "wire cutters", "side cutters" and "diagonal cutters" all mean the same thing, but different terminology is used in different areas.
Certainly, no one is going to look at you funny if they ask you to pass them a pair of wire cutters and you pass them a pair of side cutters.
If they do, shrug your shoulders, say "What?" and send them to me.
(there's more of a difference in the wire cutters used to cut different size wire and the way the jaws of those cutters meet or come together than there is a recognized or universally understood difference in the meaning of those three terms)
Kinda like calling one tool a "pair of Vice Grips" and another tool a "pair of Locking Pliers".
You humans often use more than one word for the same thing, and it's confusing to the rest of us who are just visiting this planet.
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