Is it great-grandma, great grandma, Great-grandma, Great-Grandma, or Great Grandma? Thanks!

3 answers

great-grandma :]
If you use it in a sentence like this:
My great grandma lives in California, it is not capitalized.

However, if you use it place of her name, it is capitalized:
Don't tell Great Grandma about her surprise party.

Most sources do not use a hyphen -- but that is not a hard and fast rule.
Thank you!