Monohybrid crosses only look at one genotype. Whereas dihybrid crosses look at two genotypes.
An example of a monohybrid cross would be AA x aa, where A represents the dominant allele, and its phenotype is the colour red, and a represents the recessive allele, and its phenotype is the colour white.
An example of a dihybrid cross would be SSYY x SsYy, where the letter S represents the size, dominant phenotype is large, recessive is small, and Y represents the colour, dominant phenotype is yellow, recessive is green.
