[foo
t-lam-bert] 
| a unit of luminance or photometric brightness, equal to the luminance of a surface emitting a luminous flux of one lumen per square foot, the luminance of a perfectly reflecting surface receiving an illumination of one foot-candle. Abbreviation: fL |
| foot-lam·bert (fŏŏt'lām'bərt) n. Abbr. fL A unit of luminance equal to 1/π candela per square foot. |