I was working in the garage and the power went out but I didn't blow a fuse. What could be the problem?

I was working in the garage and the power went out but I didn't blow a fuse. What could be the problem?
Just in the garage or in the house too.

A breaker that didn't throw, a bad connection, a tripped GFI are 3 possibilities.

Not sure what a GFI is?

You could have dropped a neutral leg too. A GFCI is a ground fault and could be a breaker in your panel or a GFCI outlet in the garage. When they have tripped you should see a small red "flag" to show it is tripped. A breaker needs to be reset by switching totally off and then back on, the flag should disappear. An outlet would have two small rectangular button, one to test and one to reset, if you find one of these try pushing the reset. Since you say a"fuse" did not blow I will assume you have an older panel, test the lines coming from the panel toward the garage with a tester but be careful.