Help me, wat is a piza?

Hi, i am from Africa. I just moved here hopeing to find a beter life. I was walking throo the streets enjoying my new life wen i walked intwo a bilding and a person led me to a tabl. then won person asked me if i wanted the spesal of the day......... i asked hir wat that was and shee sayd it was a piza............... wat is a piza?