Eavesdropping is possibly a backformation of eavesdrop, the portion of a house where rainwater will drip off. A person who surreptitiously stands at the windows to overhear is known as an eavesdropper. That makes a lot of sense, particularly in close-packed medieval cities where the houses were right on the streets. The French are more direct about the term, saying ecouter aux portes, or listen at the doors. Makes sense to me. That explanation is a lot better than the one for the expression “raining cats and dogs” which supposedly came from the habit of cats and dogs climbing up into the eaves of houses to sleep. When rain came the cat and dogs would jump out of the eaves and so it looked like it was raining cats and dogs as well as rain. I think this is a silly explanation since no self-respecting cat or dog would go to that much trouble to find a place to sleep. Usually they look for some place that is warm, dry and easy to reach–qualities house eave are notably lacking.
It used to be a lot easier to eavesdrop in the days of party lines when three or four families shared a telephone line. Each household had a distinctive ring (ours was two shorts and a long) and all you had to do to listen in on a conversation was pick up the receiver. Maybe this is where I got into the habit of eavesdropping. I can blame it on Ma Bell.
Sometimes, though, a good eavesdropping opportunity doesn’t pay off. I was in a store the other day when I heard a rather agitated woman ask a clerk to speak to the manager. Bingo! I sidled up to them, pretending to look at some merchandise. I was all ears. When the manager came up I expected a good listen, but all the woman wanted to do was ask something about the store’s inventory. Apparently her default expression and manner was one of agitation. So it didn’t work out that time, but sometimes it does, and it’s the best free entertainment around.