Other forms: overheads
Overhead means directly above you. A plane crosses the sky, a bulb hangs from the ceiling, branches meet over a lane — all overhead.
As an adverb it comes after the verb: geese flew overhead, thunder rumbled overhead. As an adjective it stands in front of the noun: overhead cables, an overhead locker, the overhead projector your teacher wheeled in. The noun is the surprise. A business's overheads (British) or overhead (American) are the costs of simply existing — rent, heating, insurance, wages you pay whether or not you sell a thing. Computing borrowed that noun for the extra time or memory a process spends on nothing useful.
1adverboverheadDirectly above; in the sky or the space above your head.
“A helicopter circled overhead for twenty minutes.”
2adjectiveplacedPlaced above head height.
“She reached up and shut the overhead locker.”
3nounregularThe regular costs of running a business, apart from materials and production.
“Moving to a smaller unit cut their overheads in half.”
4nounextraExtra time, effort or resources a process uses beyond the work itself.
“Encrypting every message adds a little overhead.”
Overhead is as plain as it looks: Old English oferhēafod, over plus head, saying the same thing for a thousand years. Low German and German built the same compound, överhoopt and überhaupt.
Old English
oferhēafod
Middle English
owerheved
English, today
overhead
From Middle English owerheved, over-hed, over hede, from Old English oferhēafod, equivalent to over- + head. Compare German Low German overhoopt, överhoopt, German überhaupt. overchief.
Etymology from Wiktionary, CC BY-SA