Which prefix indicates 'large or great'?

The prefix "mega-" is derived from the Greek word "megas," meaning large or great. It is commonly used in medical terminology to denote size or magnitude, suggesting something that is significantly larger than normal. For example, "megacolon" refers to an enlarged colon, and "megadose" indicates a significantly larger than normal dose of a medication.

In contrast, the other prefixes have different meanings: "mal-" typically indicates something bad or abnormal, "micro-" refers to something small or minute, and "eu-" suggests a sense of good or well. Thus, these options do not convey the meaning of 'large or great' as effectively as "mega-" does.