The term 'SUFFIX WITH PLANET' can be solved with two three-letter words: OID and ARY. OID is a suffix derived from the Greek word 'eidos, ' meaning 'FORM' or 'SHAPE.' It is commonly used in scientific terms to refer to something that is shaped like a certain object, such as an asteroid or a planetoid. ARY is a suffix derived from the Latin word 'arius, ' meaning 'pertaining to.' It is often used in scientific terms to refer to something that is related to a certain object, such as a planetary system or a stellar cluster.