IPA: /ˈmʌltaɪˌsaɪdɪd/
KK: /mʌltaɪˈsaɪdɪd/
Having more than one side or face.
The architect designed a multisided building that was both modern and functional.
Multisided → It is formed from "multi-" (meaning many) and "sided" (from the Old English "side", meaning a surface or aspect). The word "multisided" means having many surfaces or aspects.
Think of 'many' ('multi-') surfaces or aspects ('sided') — that's what multisided means.
No commonly confused words.