The word litter has three seemingly unrelated meanings: a stretcher used to carry a person lying down; debris lying on the ground like hamburger wrappers and paper cups; and a group of baby animals (think kittens or puppies) born to the same mother at the same time. Surprisingly these all ultimately come from the same Latin word lectus meaning bed via Old French litiere. The "stretcher" meaning has a more obvious connection to "bed"; at one time a litter was a bed or seat carried on the shoulders of four men. The "garbage" meaning came from the practice of spreading straw on the floor for bedding for people or animals to sleep on. The "baby animals" meaning makes sense if you think of them as litter-mates - sharing the same birthing bed.
There are also pairs of similar words with similar meanings, but having very different origins. When I remember or find some I will do a post on them. Any suggestions?