Lamp weighing relatively little (5)

I believe the answer is:

light

I believe this clue is a double definition.

'lamp' is the first definition.
(I've seen this before)

'weighing relatively little' is the second definition.
(I've seen this before)

(Other definitions for light that I've seen before include "Source of illumination" , "weighing relatively little" , "Airy; not heavy" , "Torch" , "Pane of glass" .)

I've seen this clue in The Times.

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