GRANDPARENT
grandparent
(noun) a parent of your father or mother
Source: WordNet® 3.1
Etymology
Noun
grandparent (plural grandparents)
the parent of someone's parent
Antonyms
• (with regard to ancestry) grandchild
Hyponyms
• (by grandparent's gender) grandmother, grandfather
• (by grandparent's and parent's genders) maternal grandmother, maternal grandfather, paternal grandmother, paternal grandfather
Verb
grandparent (third-person singular simple present grandparents, present participle grandparenting, simple past and past participle grandparented)
synonym of grandfather
Source: Wiktionary