
Grandfather
Gender Specific
Grandfather refers specifically to a male relative; there's no female equivalent for this term.
Her grandfather, not grandmother, served in the war.
Two Generations Up
Grandfather indicates a direct ancestor two generations above you, not just any older relative.
I learned gardening from my grandfather, my mom's dad.
Affectionate Term
Often used endearingly for someone who may not be a relative but is old and cherished.
We all call him grandfather because he's so caring.