Each box inside a punnett square represents one?

Answer: one genotype of the offsprings.

Explanation: A punnett square is a diagram used I'm predicting the possible genotypes of a cross between two organisms. Punnett square is used to predict the probability that an offspring will have a particular genotype. In punnett square, the parents' genotypes are written on the top and the left side of the square while the possible genotypes of their offsprings are written in the boxes.