Candling

a long, usually slender piece of tallow or wax with an embedded wick that is burned to give light.
something resembling a candle in appearance or use.
Optics.

(formerly) candela.
Also called international candle. a unit of luminous intensity, defined as a fraction of the luminous intensity of a group of 45 carbon-filament lamps: used from 1909 to 1948 as the international standard.
a unit of luminous intensity, equal to the luminous intensity of a wax candle of standard specifications: used prior to 1909 as the international standard.
Abbreviation: c., c.

to examine (eggs) for freshness, fertility, etc., by holding them up to a bright light.
to hold (a bottle of wine) in front of a lighted candle while decanting so as to detect sediment and prevent its being poured off with the wine.
burn the / one’s candle at both ends. burn1 (def 54).
hold a candle to, to compare favorably with (usually used in the negative):
She’s smart, but she can’t hold a candle to her sister.
worth the candle, worth the trouble or effort involved (usually used in the negative):
Trying to win them over to your viewpoint is not worth the candle.
Historical Examples

The Dollar Hen Milo M. Hastings
Every Step in Canning Grace Viall Gray
Every Step in Canning Grace Viall Gray
Our Domestic Birds John H. Robinson
The Dollar Hen Milo M. Hastings
Balsamo, The Magician Alexander Dumas
Mother Owen Wister
The Dollar Hen Milo M. Hastings

noun
a cylindrical piece of wax, tallow, or other fatty substance surrounding a wick, which is burned to produce light
(physics)

See international candle
another name for candela

burn the candle at both ends, to exhaust oneself, esp by being up late and getting up early to work
(informal) not hold a candle to, to be inferior or contemptible in comparison with: your dog doesn’t hold a candle to mine
(informal) not worth the candle, not worth the price or trouble entailed (esp in the phrase the game’s not worth the candle)
verb
(transitive) to examine (eggs) for freshness or the likelihood of being hatched by viewing them against a bright light
n.

see:

burn the candle at both ends
game is not worth the candle
hold a candle to