| PHOT | CGS unit of illumination, equal to one lumen per square centimetre or 10,000 lux (4) |
| HECTARE | Metric unit of area equal to 2.471 acres or 10,000 square metres (7) |
| TAPEMEASURE | Tool with centimetre or inch markings (4,7) |
| SQUARENUMBER | 100 or 10,000 but not 1,000 |
| LAMBERT | Unit of brightness, equal to one lumen per square centimetre (7) |
| FOOTCANDLE | Former unit of illumination, equal to 10.764 lux |
| LX | A unit of illumination equal to 0.0929 foot-candle, abbreviated |
| LUX | One lumen per square meter |
| STILB | CGS unit of luminance equal to one candela per square centimetre; from Greek, 'to glitter' (5) |
| GAUSS | CGS unit of magnetic flux density, equal to one maxwell per square centimetre (5) |
| ESCE | Suffix with opal, lumen, or evan |
| UNIT | League, liter, or lumen |
| MILLIBAR | Usual unit of barometric pressure, equivalent to 100 pascals or 1000 dynes per square centimetre (8) |
| ELON | Southern university with the motto "Numen lumen" |
| DIMS | Lowers the lumens of |
| LUXES | Lumen per square meter, pl. |
| LUXOR | Gold unit of illumination first found in town in Egypt (5) |
| PIXEL | Unit of illumination on a display screen (5) |
| LUD | Unit of illumination - for a Hubei "sen" abbr. |
| ELM | English short of lumen, then timber |
