Correctness is the quality of being right, accurate, or free from error. When you check your math homework for correctness, you're making sure your answers match what the problems actually require. When a scientist verifies the correctness of her measurements, she's confirming they're accurate and reliable.

Correctness matters differently in different situations. In mathematics, correctness is absolute: two plus two equals four, not 4.1 or “close to four.” But in writing, correctness might mean following grammar rules while still leaving room for creative expression. A sentence can be grammatically correct but still sound awkward or boring.

The word often appears when people are checking, testing, or verifying something. A chef might taste a sauce to check its correctness, meaning whether the flavors are balanced just right. A builder uses a level to verify the correctness of a shelf's angle.

People sometimes confuse correctness with perfection, but they're not the same thing. A correct answer is simply the right one, while perfection suggests flawlessness in every detail. Your solution to a word problem might be mathematically correct even if your handwriting is messy or you took longer than expected to solve it.