Total comp sometimes includes stuff like Options (which might never cash out), bonuses (based on things you cannot control like quarterly sales) or include benefits. So for example if your company pays a dental insurance that costs 2,000 a year it might say your salary is 50k but your total comp is 52k.

So an example could be. Your salary is 50k, your benefits are calcualted to be 10k, your options ammount to 20k and your bonus is 20k.

Your total comp is 100k, but because options vest slowly you only make 1/4 of that and the bonus did not work out, so your take home salary was 55k + benefits.

This can change depending on the company, role, country, contract etc. Its not really like total comp is a legal definition.