In punctuation, a colon is the mark made by stacking two periods (:). The colon can be used to separate the hour and minutes in time (7:30 a.m.) or to introduce a list or a quotation.
A colon is also a unit of money in both Costa Rica and El Salvador. It equals 100 centimos in the former and 100 centavos in the latter. When you travel to Costa Rica, you can trade dollars for colons. In medical terms, your colon is part of your digestive system, and its purpose is to extract water from solid waste. In humans, there are four parts of the colon: ascending, transverse, descending, and sigmoid.