1. A unit of illumination equal to one millionth of a lux, used to measure very low light levels.
Usage: technical; scientific; symbol: µlx

Examples

• The sensor can detect light levels as low as 0.1 microlux.
• Astronomers use microlux measurements to study faint starlight.
• The laboratory's dark chamber maintained illumination below 5 microlux.
• Night vision equipment is calibrated to operate in microlux conditions.