Definition of red-eyes:
(n) :
(countable, US, aviation, travel, colloquial, also attributively) An overnight airplane flight or train trip.
(n) :
A drink made by adding a shot of espresso to a cup of coffee.
(n) :
(Canada, regional) A drink consisting of beer with tomato juice.
(n) :
(US, slang) A strong but poor-quality whiskey.
(n) :
(countable, uncountable, medicine) Redness of the conjunctiva; especially when caused by conjunctivitis (pink-eye).
(n) :
(countable, uncountable, photography) Redness in the eye(s) of someone in a colour photograph, as an unwanted consequence of light from a flash reflecting off blood vessels in the retina.