Japanese for grandfather

what do japanese children now a days call their grandfather?
my friend told me, you can call him jiichan.
but it's too long. i want a short one.
is their a short japanese name for grandfather?

JiJi

"Jiijii" is common

My father is called "jiiji" by his grandchild.

"jiichan" is too long?? It's only two syllables. It's very short. What are you thinking of? A one letter word? It does not exist in Japanese.

"O-jiichan" (with a polite "o-" at the head) would be a common way. As Chopo mentioned, "Jiichan" is only two syllables, not long at all :)

That's not long at all. What you're looking for something like "gramps"?! -_-!

It also depends on how you want to be perceived or how close you are to your granpa.

Anyway, as AK said, schoolchildren commonly call their grandfather "o-jiichan".
"jiji" and "jiijii" are baby talk.

About to call "jiichan", I feel he live together with his grandfather or meet frequently.

If "jiichan" is too long, just call him "G". That'll sound cool.

Whatever, just don't call him "ji-jii" with a longer second sylable. There is a huge difference between "jii-ji" and "ji-jii".

Well, technically, "jiichan" is four "syllables," or morae (ji-i-cha-n)--or maybe four and a half, depending on how "cha" is counted--and "gramps" would parse out to gu-ra-m-pu-su" or five morae. So, as Japanese words go, "O-jiichan" or "Jiichan" is fairly short. Go with it!