The prefix 'OMNI' is universally used to describe something that is all-encompassing or all-inclusive. It is derived from the Latin word 'omnus, ' which means 'all.' This prefix is often used to describe something that is universal, such as an omniscient being or an omnipresent force. It can also be used to describe something that is all-encompassing, such as an omnibus bill or an omnivore. In short, the prefix 'OMNI' is used to describe something that is all-encompassing or all-inclusive.