ルクス

also: ルックス

ル

ク

ス

Common wordFreq.FrequencyTop 50,000

Meanings

lux (unit of illuminance)

Scientific and technical term for illuminance; one lux equals one lumen per square meter. Used in lighting, photography, and engineering contexts.

from French

この部屋へやの照しょう度どは約やく500ルクスです。
The illuminance in this room is about 500 lux.
ルクスメーターで明あかるさを測そく定ていした。
I measured the brightness with a lux meter.

See all 5 example sentences ›

Usage patterns

照しょう度どは〈数すう〉ルクスだthe illuminance is X lux
この部屋へやの照しょう度どは約やく500ルクスです。
The illuminance of this room is about 500 lux.
〈物もの〉の明あかるさをルクスで測はかるto measure the brightness of something in lux
デスクライトの明あかるさをルクスで測はかってみた。
I measured the brightness of the desk lamp in lux.

Related words

照しょう度ど
照度 is the general Japanese term for illuminance, while ルクス is the specific SI unit used to express its value.

Don't confuse with

ルーメン
ルーメン measures the total light output of a source, whereas ルクス measures how much of that light actually falls on a surface, so the two are often mixed up.

Word family

ルクスメーター
lux meter; illuminance meter

Written forms

ルクスUsage79%
Standard katakana spelling for the unit of illuminance, from French 'lux'.
ルックスUsage21%
Variant spelling; less common than ルクス. May be confused with ルックス (looks, appearance).

Etymology

From French 'lux', a unit of illuminance in the International System of Units (SI). The variant ルックス may reflect an alternative transliteration or influence from English pronunciation.