I always thought of a colander (or cullander) as a bowl with perforations inside a solid bowl with a lid. The perforated inner bowl is rotated by turning a handle on the lid. We use it mainly for removing the excess water from things like lettuce after washing it.

No, no! At least in my ideolect, that's a salad spinner. One of my VERY FAVOURITE kitchen toys. (I love kitchen toys with gears or teeth - salad spinner, egg beater, can opener...). A colander is often plastic (but can be metal), and is more plastic than holes (by surface area), while a sieve is metal mesh, formed in a bowl shape, and is more holes than metal.

Here are some pics:
Colander: http://www.cybercucina.com/cgi-local/SoftCart.exe/ccdocs/products/3535-x.html?E+cybercucina
Sieve (hanging on the wall in the picture, with bonus Indonesian vocabulary!): http://www.seasite.niu.edu/Indonesian/Themes/Houses/kitchen/Default.htm