The prefix that means "all" is "omni-". To determine this, you can break down the prefix and its meaning. In this case, "omni-" comes from the Latin word "omnis," which means "all." So, whenever you see the prefix "omni-" attached to a word, it indicates the concept of "all" or "every." For example, words like "omniscient" (all-knowing) and "omnipotent" (all-powerful) both use the prefix "omni-" to convey the notion of totality or universality.
