|Definition - According to Silva Rhetoricae, the word colon is "roughly equivalent to clause in English, except that the emphasis is on seeing this part of the sentence as needing completion, either with a second colon (or membrum) or with two others (forming a tricolon)."|
Example - A tricolon (the 3 parts are numbered):
(1) You have not considered the well-being of my stomach,
(2) nor have you seen to the welfare of my false teeth,
(3) nor have you succumbed to my advances.
Etymology - The word derives from the Greek kolon, part of a verse (it literally means "limb").
Note: it initially denoted an independent clause, then it evolved to denote the punctuation mark that was used to set off independent clauses.
Oxford English Dictionary - Its first citation is from 1589:
"The auncient reformers of language, invented, three manner of pauses …
The second they called colon, not a peece but as it were a member for his larger length,
because it occupied twise as much time as the comma."
(Puttenham Eng. Poesie ii. iv. [v.] (Arb.) 88 )