Basic means forming the essential foundation of something, like the fundamental parts you need before you can build or understand anything more complex. Basic math skills include addition, subtraction, multiplication, and division: you need these before you can tackle algebra or geometry. Basic swimming skills mean you can float and paddle before learning fancy strokes.

When describing something as basic, you mean it covers the most important elements without fancy extras. A basic sandwich might be just bread, meat, and cheese, nothing complicated. Basic training in the military teaches new recruits the essential skills every soldier needs to know.

The word can also describe something simple or plain, sometimes disappointingly so. A basic cell phone makes calls and sends texts but doesn't have all the features of a smartphone. In this sense, basic isn't necessarily bad: sometimes simple and straightforward is exactly what you need.

You might hear people use basically to mean “in the most important way” or “essentially.” When you say “I'm basically finished with my homework,” you mean you've completed the main parts, even if a few details remain. Or when explaining something complicated, you might start with “Basically, here's what happened...” before laying out the most important facts.