It's code that produces a value - that's all. Many, many things in JavaScript are expressions. Maybe it would help to see something that's not an expression? (writing on one line just for brevity) if (condition) { doThingA() } else { doThingB() } In JS, the if/else is a statement, not an expression, because it doesn't produce a value. For example, you cannot do this: let result = if (condition) { doThingA() } else { doThingB() } In some other languages (not JS), the if/else is an expression that produces a value. Same with switch, in JS it's a statement (no value) but in some other languages it's an expression (produces a value). Some other examples of expressions in JS: literals (strings, numbers, booleans, array literals, object literals, function literals, etc.) variables (like x is an expression that produces a value of whatever is in variable x) function calls Unary expressions (negation, logical not, increment/decrement, etc.) binary expressions (arithmetic, bitwise, logical, etc.) ternary expressions (conditional operator) quarternary expressions (just kidding!) Read more: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Expressions_and_Operators Answer from Tubthumper8 on reddit.com