what four hebrew letters are on the dreidel, & what do they mean, also, what are three ingredients in latkes?

Answer 1

Esther's answer is great, but I would like to add to her sayings that the initials Nun Gimel Heh Shin (נגהש- nes gadol hayah sham) are written on dreidels of Jewish communities outside Israel, as it says "a great miracle happened there".
The initials on the dreidels in Israel are Nun Gimel Heh Peh (נגהפ): nes gadol hayah po- a great miracle happened here.

Answer 2

The letters are:
Nun (nothing)
Guimel (all)
Hey (half)
Shin (put)

They are refered to the Hanukkah miracle
"Nes Gadol Haya Sham" (A great miracle happened there)

The latkes ingredients are potatoes, onion, eggs and flour...