Grandfather
Definition 1 of 3
Pro Tip 1/3
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.
Pro Tip 2/3
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.
Pro Tip 3/3
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.