candle-power

A sixty candle-power lamp illuminates the reading room.

Definition

1. Noun:
   • Unit of luminous intensity: "candle-power" is a former unit of measurement for the intensity of light, based on the light emitted by a standard candle. It is now largely replaced by the candela.
   • Brightness of a light source: In informal usage, "candle-power" refers to the brightness or luminous output of a lamp or bulb, often expressed as a number (e.g., "60 candle-power").

Usage Examples

• As a unit of measurement:

  • The old lighthouse used a lamp with a rating of one million candle-power. (The lamp's light intensity was equivalent to one million standard candles.)
  • Early car headlights were often rated at 32 candle-power. (The headlights emitted light equal to 32 candles.)

• In informal descriptions:

  • This flashlight has a candle-power of 100. (The flashlight's brightness is comparable to 100 candles.)
  • The sixty candle-power lamp lit the entire room. (The lamp's brightness was 60 candles.)

Advanced Usage

• "Candle-power" as a historical term: In the 19th and early 20th centuries, "candle-power" was the standard unit for measuring light, defined by a specific type of candle (e.g., spermaceti candle). It was officially replaced by the candela in 1948.

  • The British standard candle-power was based on a candle burning at a specific rate. (A historical definition of light intensity.)

• Figurative use: Occasionally used metaphorically to describe mental or spiritual illumination.

  • Her wisdom had a candle-power that guided us through confusion. (Her insight provided clarity, like a bright light.)

Variants and Related Words

• Candlepower (n): alternative spelling (one word).

  • The candlepower of the searchlight was astonishing. (The brightness of the searchlight was very high.)

• Candela (n): the modern SI unit for luminous intensity, replacing candle-power.

  • One candela is roughly equivalent to the light from one standard candle. (The modern unit is similar to the old candle-power.)

Synonyms

• Luminous intensity: the measure of the amount of light emitted per unit solid angle.
• Brightness: the perceived intensity of light from a source.
• Lumen (per steradian): a related unit for total light output, though not identical to candle-power.

Related Idioms

• "Not a candle-power to spare": an idiomatic expression meaning having minimal or no extra light or energy.
  • The old lantern had not a candle-power to spare, barely lighting the path. (The lantern was very dim.)

Note: "Candle-power" is primarily a technical or historical term; it is rarely used in modern everyday conversation except in reference to antique lighting or specialized contexts.