If you increase something by half, half of the original amount is added to it. If you decrease it by half, half of the original amount is taken away from it.
The number of 7 year olds who read poorly has increased by half over the past 5 years.
Cutting food intake by half is an incredibly difficult thing for anyone to do.
Synonyms: excessively, very much, considerably More Synonyms of by half
See full dictionary entry for half
by half in British English
by an excessive amount or to an excessive degree
he's too arrogant by half
See full dictionary entry for half
by half in American English
considerably; very much
See full dictionary entry for half
Examples of 'by half' in a sentence
by half
Simmer for about 25 minutes until the sauce has reduced by half.
Times, Sunday Times (2015)
Boil until reduced by half, about 5 minutes.
Times, Sunday Times (2012)
He reduced the amount by half, to 30,000.
The Sun (2015)
(idiom)
Definition
to an excessive degree
He's just too clever by half.
Synonyms
excessively
very much
considerably
Their dinner parties had become considerably less formal.
See half
Additional synonyms
in the sense of considerably
Their dinner parties had become considerably less formal.