(1) The prefix root word of megalithic is mega, suggesting that the monument is large, complex, or has several uses. (2) This root word is also used in words like the following, even though it may have a slightly different meaning: megaphone (using the root word to mean loud), megahit (using mega as to mean well-known), and megabyte (using the root word to once again mean large). Two other prefixes you could use to mean large are maxi and macro. these are used in words like maximum and macrobiotic.
