Omitted area of metal to hinder crack development

[frankiee]

Sorry to bother.
I forget the name of the area in a structure, such as a frame, where they purposely cut out where stress could start a crack.
I was wondering if someone could tell me the name of that area so that I can do some research.

 

[jike]

Opening? Cope? rathole?

 

[civilperson]

Dogbone

 

[kslee2006]

I guess you are talking about the "Fillet" which is purportedly curved around sharp corners to avoid stress concentration.