45 auto/acp cartridge name confusion

[Grumpy]

What is the difference? I accidentally grabbed the wrong box of ammo for my new 45ACP gun. It is 45 auto Hornady Critical Defense 185 grain.

The store had tons of this ammo and not much ACP. Is this something that is supposed to able to be shot in an ACP application or is there a unique gun for this round?

If I cannot shoot this ammo out of my gun I have to find someone to buy it. Round seems about the same size in diameter but maybe just a smidge shorter. Do not have a micrometer to measure adequately.

If I cannot use it, anyone want to buy it?

45-auto= a short way to say,
45 ACP
45 Automatic Colt Pistol

worth watching all the way through then thinking carefully,
https://www.concealedcarryuniversit...d-t2?cf_uvid=3eee8beb3826def12fb6ba51052e0ce6
https://en.wikipedia.org/wiki/.45_ACP

http://www.m1911.org/full_history.htm

http://www.militaryfactory.com/smallarms/detail.asp?smallarms_id=12

https://www.americanrifleman.org/articles/2011/3/7/colt-history-a-look-back-at-the-1911/