You mean syllables.
Click here for more information and rules.
How do I know words syllabuses?
2syllabuses,is there any rule?
PS Anti-mnemonic: A syllabus is what you learn and a syllable is what you say. Hmm. Perhaps it should be 'A syllabus is about studying and a syllable is about sound liaisons'. (A bit grandiloquent for my liking.)