The eaves are the part of a roof that overhangs the wall. Under the eaves, birds in the eaves, clear the eaves.
The overhang throws rainwater clear of the wall, which is the whole point, and the deeper it is the drier the building stays. The word is plural in form and always has been, and eavesdrop comes from standing beneath it to listen.
1nouneavesThe part of a roof that overhangs the wall.
“Swallows built their nests under the eaves of the old barn.”
eaves is a part.
Old English efes names the roof edge, from a Germanic root meaning edge.
Proto-Indo-European
*upér — above; over
Proto-Germanic
*ubiswō
Proto-West Germanic
*ubisu — hall
Old English
efes
Middle English
eves — projecting lower edge of a roof
English, today
eaves
Built from
From Middle English eves (“projecting lower edge of a roof”)euez, euese, evese, ewse, eyues, eyuis, hevese, ouese, ouise, ovese, from Old English efes, yfes, ofes (“edge of a roof”), from Proto-West Germanic ubisu (“hall”), from Proto-Germanic ubiswō (compare Gothic 𐌿𐌱𐌹𐌶𐍅𐌰, Old High German obasa (“hall; porch; roof”)), perhaps ultimately from Proto-Indo-European upér (“above; over”) (whence over).
Etymology from Wiktionary, CC BY-SA