there's this word eavesdropping or eavesdrop, which I looked over in oxford and several other places. the closest I got to understanding it was that it originated from an obsolete noun "eavesdrop", meaning the ground on to which water drips from the eaves. But how did come to it's current usage? I'm curious. anyone else?
There was an ancient custom that stopped a landowner from building within two feet of his boundary, for fear that the water cascading off the eaves might cause problems for his neighbor. By the end of the medieval period, the word eavesdropper had been invented to describe someone who stood within this strip of ground, under the projecting eaves and close to the walls of a building, in order to listen surreptitiously to the conversations within. The verb eavesdrop in the same sense came along about a century later.
The most complete explanation I've found is here
Eavesdrop, or originally eavesdrip, was originally a noun referring to the water dripping off the eaves of a building or ground on which such water would fall. From medieval times there were legal restrictions on building close to one’s property line so that the eavesdrop would not damage the neighbor’s land. From the Kentish Charter of year 868 (yfæs drypæ = eavesdrip):
"An folcæs folcryht to lefænne rumæs butan twigen fyt to yfæs drypæ." (A right of the people to live without restraint except it is uncertain in the eaves drip.)
The word eavesdropper, meaning one who stands in the eavesdrop of a building and listens to conversations within, dates to 1487. From the Nottingham Borough Records of that year, mostly in Latin except for the word in question:
"Juratores...dicunt...quod Henricus Rowley...est communis evys-dropper et vagator in noctibus." (The court…was told…under oath that Henry Rowley…is a common eavesdropper and a prowler in the night.)
Or for a fully English quote, we go to c.1515 and Richard Pynson’s Modus Tenendi Curiam Baronis:
"Avb, Euesdroppers vnder mennes walles or wyndowes...to bere tales."
The verb to eavesdrop makes is not recorded until 1606. It’s not certain whether it’s a backformation of eavesdropper, or if that noun comes from the verb which existed, unrecorded, in earlier years. From the 1606 comedic play Sir Gyles Goosecappe:
"We will be bold to evesdroppe."
If a man set himself to listen through a window or keyhole to what was going on in a house he had to stand so close that the eavesdropping would fall upon him, for which reason all prying persons, seeking by secret means what they have no business to know, came to be called eavesdroppers. It was a punishable crime.
(Source: Oxford English Dictionary, 2nd Edition.)
Originally this word had nothing to do with snooping.
Eavesdrop started off literally: first it referred to the water that fell from the eaves of a house, then it came to mean the ground where that water fell.
Eventually, eavesdropper described someone who stood within the eavesdrop of a house to overhear a conversation inside.
Over time, the word obtained its current meaning: "to listen secretly to what is said in private."
Source: MW Dictionary
In German there is the word die Traufe. That is the edge of the roof where the rain water comes down when the roof is not provided with a gutter. The word Traufe is connected with triefen (to drip) and tropfen (to drop). Etymonline has an explanation for eaves that I find a bit difficult. I'm pondering about whether eaves is not somehow connected with Latin aqua / akva, agva/ and its plural aquae meaning water/waters. In German aqua has related forms die Aue (meadow beside a river) and Ache (proper name for a small river). In French aqua has become eau; the e was added to distinguish eau from au (a form of the definite article).
aquae: If you leave out q and read u as v you get avae. Change a to ae and e, then you get eve. And add plural s as aquae is a plural and you get eves. Now you might insert an a to show that the original word had a. This is just an idea that beside the usual explanations there might be other possibilities. The idea of eavesdrop would then be: the edge of the roof where the rain-water or waters come down when the roof has no gutter.