[Grammar] The thieves gained entrance through... or The thieves gained entry through....

[D.C. Foster]

I found the following two sentences in a grammar book and was asked to choose which one was correct. I at first thought that "The thieves gained entrance through the window." sounded correct but then when I checked online I found both? Are both correct or is there one that is more grammatically correct than the other? Thanks.

 

[SoothingDave]

Entry. "Forced entry" is the crime.

 

[D.C. Foster]

Entry. "Forced entry" is the crime.

Thanks so much for your help. So it's correct to say then that when people say "he gained entrance through..." it's actually incorrect?!

 

[Roman55]

I am not a teacher.

It's not incorrect to say 'gain entrance' but, according to this dictionary, (definition 2.2) it doesn't have the same meaning as 'gain entry'. It's the right to enter somewhere.