The term grandparent means the parents of a person's parents. The term grandparent is used for both male and female genders. The male grandparent is a grandfather. The female grandparent is a grandmother.
When looking at the relationship from the point of veiw of the grandparent, the term grandchild is used. A grandchild is the child of a person's child. It can also be used based on gender. Grandchild is correct for either gender. Grandson is male. Granddaughter is female.
Example of Grandparent/Grandchild[change]
For example: Bob has a son. That son has 2 children, a boy (Bill) and a girl (Mary). Bob is the grandfather (male grandparent) of both Bill and Mary. Bill is the grandson (male grandchild) of Bob, and Mary is the granddaughter (female grandchild) of Bob. Bob's wife would be the grandmother of both Mary and Bill.