What is another word for punnet square?

There isn't a true synonym for "Punnett square" as it's a specific term used in genetics. However, you could use other phrases to describe the same thing, depending on the context:

General alternatives:

* Genotype grid

* Genetic diagram

* Probability table

* Cross diagram

More specific alternatives:

* Dihybrid cross diagram (for crosses involving two traits)

* Monohybrid cross diagram (for crosses involving one trait)

* Pedigree chart (for illustrating inheritance patterns in a family)

Ultimately, the best alternative depends on what you're trying to communicate and the context of your writing.