What's an aglet?

An aglet is the thing added to the end of a cord to stop the cord fraying and make it easier to pass through a hole (for example, for lacing your doublet to your pants). There are also a whole range of ones which were there purely for decorative purposes, but I'm mostly interested in the ones used to make it easier to tie your clothes together. Your clothes, not your shoes, you ask? Yes; the use of aglets on shoelaces is a relatively recent thing; circa 18th century, I think.