grandparent
US: /ˈɡɹændˌpɛɹənt/
UK: /ɡɹˈændpeəɹənt/
Advanced English dictionary
+ noun[usually pl.] the father or mother of your father or mother: The children are staying with their grandparents.
Collocation
ADJ.
maternal, paternal | doting
a present from his doting grandparents
QUANT.
set
I've sent photos of the children to both sets of grandparents.