Merriam-Webster's Collegiate® Dictionary, 11th Edition
COLON
I. noun (plural colons or cola)
Etymology: Middle English, from Latin, from Greek kolon
Date: 14th century
the part of the large intestine that extends from the cecum to the rectum,
II. noun (plural colons or cola)
Etymology: Latin, part of a poem, from Greek kōlon limb, part of a strophe
Date: circa 1550
a rhythmical unit of an utterance,
2. plural colons a punctuation mark : used chiefly to direct attention to matter (as a list, explanation, quotation, or amplification) that follows, the sign : used between the parts of a numerical expression of time in hours and minutes (as in 1:15) or in hours, minutes, and seconds (as in 8:25:30), in a bibliographical reference (as in Nation 130:20), in a ratio where it is usually read as “to” (as in 4:1 read “four to one”), or in a proportion where it is usually read as “is to” or when doubled as “as” (as in 2:1::8:4 read “two is to one as eight is to four”),
III. noun
Etymology: French, from Latin colonus
Date: 1888
a colonial farmer or plantation owner