noun
grandpa; gramps
Affectionate, honorific term for one's own grandfather or an elderly man, used mainly by young children or in a childish, familiar register. More endearing than おじいちゃん.
おじいちゃま、おはよう！
Good morning, Grandpa!
おじいちゃまが公園に連れて行ってくれた。
Grandpa took me to the park.
Derived from おじいさん (grandfather) with the honorific suffix ちゃま, a childish or affectionate variant of さま (honorific).