Webster 1913 has a definition of
aglet but it's a little hard to understand, and unsurprisingly, a little
out of date.
Quite simply, aglets are the little
plastic things on the ends of your shoelaces (and you thought it was going to be something dirty...) which are
very useful for initially lacing up your shoes. I had a pair of
12 hole boots, and it took about half an hour as I had old laces without them.
Duct tape makes quite a good substitute,
scotch tape an average one - it'll get you through one lacing, but I suppose that's all you really need.
'Aglet' is also a useful tool in checking whether you have a good
dictionary; see if it's in there.