A college diploma is a certificate earned when a student achieves graduation from an accredited college program, earning anywhere from 30 to over 70 college credits. A "diploma" is the technical term used for the piece of paper received after earning a degree.
Some schools will use the words "diploma" and "degree" interchangeably, but a degree is earned after a specific course of study and the diploma is the paperwork that recognizes this achievement. A student does not need to earn a degree in order to receive a diploma. There are work prep programs that give students diplomas to prove adequate knowledge and experience in a trade or professional course of study.