basic · fundamental · main · elementary

Branching and merging are two basic operations of revision control.

The basic job of an advertising agency is to figure out how to turn a desire into a need.

I never know what to say to people who have absolutely no grasp of the basic facts and are too ignorant to realise it.

I think your basic theory is wrong.

We've been horsing around too much; it's high time we got down to brass tacks.