Debtor owes you money. For example, your business sold a product to Mr Smith. Let us say he has 30 days to pay the money. So Mr Smith is called a Debtor to your business.
Creditor is someone whom your business owe money. Examples would be a bank from which you borrowed money, still not yet paid off
OR another business from which you purchased something, not paid the invoice it.
You need a Basic Book keeping book (Grab one from a High School student) to learn these. Also have a look at this website to learn some accounting terminology.
http://www.nysscpa.org/glossary You will find many others on the web.
Hope this is helpful to you. Best of luck.
luciana44