1half 
/ˈhæf, Brit ˈhɑ:f/ noun
plural halves /ˈhæf, Brit ˈhɑ:f/ noun /ˈhævz, Brit ˈhɑvz/ 1 : one of two equal or nearly equal parts into which something can be divided [count] ▪ She broke each cookie into halves. ▪ “Which half do you want?” “I'll take the smaller half.” ▪ Two halves make a whole. [noncount] ▪ The price has been reduced by half. [=by 50 percent; by an amount that is equal to one half of the original] — see also better half, other half 2 a [count] : either of the two equal periods of playing time in sports like football and basketball
▪ The team fell behind in the first half but rallied in the second half to win the game.
b the half : the time when the first half of a game ends
▪ The score was tied at the half. [=at halftime] 3 [count] Brit, informal : half a pint of a drink (such as beer)
▪ “What's yours?” “A half of lager, please.”
▪ The team fell behind in the first half but rallied in the second half to win the game.
b the half : the time when the first half of a game ends
▪ The score was tied at the half. [=at halftime]
▪ “What's yours?” “A half of lager, please.”
and a half 1 — used in measurements of time, distance, weight, etc., to indicate one half of the unit of measurement ▪ My daughter is two and a half (years old). [=two years and six months old] ▪ The fish was a foot and a half long. [=one foot and six inches long] ▪ ten and a half pounds [=ten pounds and eight ounces] 2 informal — used to say that something is very good, large, difficult, etc. ▪ That was a meal and a half! [=that was a very big meal] ▪ Renovating a house is a job and a half. [=is a very difficult job]
by halves
informal : in an incomplete way — used in negative statements to say that someone does things with a lot of energy and effort ▪ She never does anything by halves—it's all or nothing!
go halves also go half and half
: to share the cost of something equally
▪ We decided to go halves (with each other) on the expenses.
▪ We decided to go halves (with each other) on the expenses.
in half
: into two equal parts : into two halves
▪ She cut the apple in half.
▪ She cut the apple in half.
the half of it
informal — used to say that a situation is even worse than you think it is or than it seems to be ▪ “It sounds like you've been having some problems.” “You don't know the half of it!” ▪ Sales are down but that's only the half of it—the company is closing several stores.
too…by half
chiefly Brit, informal — used to say that someone or something has too much of a particular quality usually in a way that is annoying ▪ an arrogant politician who is too clever by half
