祖父母是指父亲的父母亲之亲属。母亲的父母称为外祖父母，又称外公、外婆。自己则分别是祖父母和外祖父母的孙儿或孙女、外孙或外孙女。

不同地方及方言对祖父母和外祖父母有不同的称谓。如吴语区称祖父母为爹爹、姆奶，称外祖父母为外爷、外婆。例如中国北方大多称祖父母为爷爷、奶奶（也有称爷爷为大大，或称奶奶为嫲嫲的，如山东部份地区），称外祖父母为姥爷、姥姥/姥娘。四川多数地方称祖父母为爷爷、奶奶，称外祖父母为家公、家婆等。客家话中称祖父为阿公(a-gong)，祖母则为阿婆(a-po)；外祖父为姐公(d͡za-gong)，祖母则为姐婆(d͡za-po)。 粤语称祖父母为爷爷、嫲嫲或阿爷、阿嫲，称外祖父母为公公、婆婆或阿公、阿婆。闽南语不论是祖父母还是外祖父母都称阿公(a-gong)、阿嬷（阿妈/a-ma）（外祖父母也可较专一地称外公(ggua-gong)、外嬷(ggua-ma)）

Grandparents are the parents of a person's father or mother – paternal or maternal. Every sexually-reproducing creature who is not a genetic chimera has a maximum of four genetic grandparents, eight genetic great-grandparents, sixteen genetic great-great-grandparents, 32 genetic great-great-great-grandparents,****genetic great-great-great-great-grandparents, etc., although the numbers will be lower in cases of pedigree collapse. In the history of modern humanity, around 30,000 years ago, the number of modern humans who lived to be grandparents increased exponentially. It is not known for certain what spurred this increase in longevity, but it is generally believed that a key consequence of three generations being alive together was the preservation of information which could otherwise have been lost; most of the time grandparents are obtained when a couple has sex and produces a child. But another occasion is when a child is adopted. an example of this important information might have been where to find water in times of drought.