watt

watt — noun

1. a standard unit for measuring how much electrical power a device uses or produce

1.nounB1
Definition

a standard unit for measuring how much electrical power a device uses or produces — for example, a 60-watt light bulb uses 60 watts of power.

Example

The old 60-watt bulb used more power than the new 10-watt LED one.

modifier form: 60-watt / 10-watt

David checked the watt rating on the microwave before plugging it in.

collocation: watt rating

Common collocations
  • rated at X watts
  • X-watt bulb / device / panel
  • X watts of power
  • X watts of electricity
  • watt rating
  • watt output

Grammar Patterns

number + watt + noun

number + watts + of + noun phrase

Usage Note

Often used as a compound modifier before a noun describing an electrical device (e.g., a 60-watt bulb). In this position the unit stays singular and is joined by a hyphen. After a number, 'watt' can be singular or plural depending on the number (1 watt, 60 watts).

Common Mistakes

I need a 60-watts light bulb.
I need a 60-watt light bulb.
When used as a modifier before a noun, the unit stays singular.
Idioms

James Watt

idiom

1736–1819 Scottish engineer and inventor whose improvements to the steam engine led to the unit of electrical power being named after him.

The watt is named after James Watt, the Scottish engineer who improved the steam engine.

James Watt's steam engine design helped power factories during the Industrial Revolution.

Word family

  • wattage
    nounB2
  • kilowatt
    nounB1
  • megawatt
    nounC1
  • gigawatt
    nounC1
  • watt-hour
    nounC1

Synonym discussion

Sense: noun/1

'Watt' names the basic SI unit of electrical power — you use it when stating a specific measurement (a 60-watt bulb). 'Wattage' refers to the amount of power expressed in watts, not the unit itself (a high-wattage device draws more current). 'Kilowatt' (1,000 watts) is the common multiple for larger appliances and electricity bills — your home energy use is measured in kilowatt-hours, not watts. 'Horsepower' is an older unit of power still used for vehicle engines and motors (1 hp ≈ 746 watts). Use 'watt' for precise electrical ratings, 'wattage' for general power level, 'kilowatt' for utility-scale figures, and 'horsepower' for engine output.

wattagekilowatt ↗horsepower ↗

Common collocations

Nouns

Phrases

  • watt per hour
  • watt rating
  • watt output
  • rated at X watts

Prepositions

Etymology

English (eponym)SI scientific naming

Named after James Watt (1736–1819), the Scottish engineer who greatly improved the efficiency of the steam engine. The scientific community adopted 'watt' as the standard unit of electrical power in the late 19th century as part of the international metric system (SI).