A unit of quantity of light (luminous energy), equal to the quantity of light radiated or received for a period of 1 second by a flux of 1 lumen. Abbreviated lm-sec.
a unit of luminous energy in the International System of Units. Abbreviated designations: Russian, Imsek; international, 1m »s. One lumen-second is the luminous energy corresponding to a luminous flux of 11m radiated or received over 1 sec.