Of or relating to a situation which exists before a particular event or process occurs, and that which exists afterwards; especially designating differences between data obtained before and after an experiment, procedure, etc., is carried out.
before–after/bɪˈfɔː ˈɑːftə/ /bɪˈfɔː ˈaftə/
1930s. From before + after. Compare earlier before and after, and also before.after.