Diaper

Diaper \DAHY-per\ or \DAHY-uh-per\ , noun;
1. A piece of cloth or other absorbent material folded and worn as underpants by a baby not yet toilet-trained
verb;
1. To put a diaper on

This week is the Second Annual Flats and Handwashing Challenge, put on by DirtyDiaperLaundry.com. As a participant and non-mommy-topic blogger, I am going to spend this week talking about diaper-related words. But first, a brief word on the challenge:
Last year a few articles came out that talked about how some families with no money for diapers were blow-drying used ones and reusing them. This is horribly unsanitary and dangerous. I believe a baby even died from an infection stemming from this practice. Cloth diaper advocates believe that there needs to be more education about the usefulness and frugality of cloth diapering for low-income families, there is even a petition to get them WIC-approved. I agree and have signed the petition.

Now, on to what you're probably here for:
Diaper dates to the mid-14th century as "fabric with a repeated pattern of figures" from Old French diaspre ("ornamental cloth; flowered, patterned silk cloth"), which ultimately derives from Medieval Greek diaspros ("thoroughly white") via Middle Latin diasprum. The Greek word is a compound of dia- + aspros ("thoroughly, entirely" + "white"). Diapers meaning "baby poop holders" has been in continuous use since 1837, though there are hints of its usage as far back as the late 16th century.

How exactly "ornamental cloth" evolved into "baby underpants" is not illustrated by the Oxford English Dictionary, but I would assume it is based on the type of cloth used for diapering a few centuries ago. From my experiences hand washing white cloth diapers, it is difficult (impossible?) to keep them white, so using colorful cloth seems like a much nicer alternative.