As nouns the difference between grandparent and kupuna
is that grandparent
is the parent of someone's parent while kupuna
is a grandparent or elder.
the parent of someone's parent
* (by grandparent's gender ) grandmother, grandfather
* (by parent's gender ) maternal grandmother, maternal grandfather, paternal grandmother, paternal grandfather
* (with regard to ancestry ) grandchild
* great grandparent
* great great grandparent
A grandparent or elder.