Glower, being the subject of jokes? (9)

I believe the answer is:

lightbulb

I believe this clue is a double definition.

'glower' is the first definition.
(something that glows)

'the subject of jokes?' is the second definition.
(as in lightbulb jokes)

'being' is the link.

(Other definitions for lightbulb that I've seen before include "Glower" , "such an illuminating thing!" .)

I've seen this clue in The Times.

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