A dictionary of Confusable Phrases: More Than 10,000 Idioms and Collocations

biannual event • biennial event
biannual event—an event that happens twice a year: The
fair, also known as Canton Fair, has been a biannual event
held in spring and autumn since 
1
957.
biennial event—an event that happens once in every two
years: This biennial event (home furnishings trade show) is
held in the spring of odd-numbered years.
big day • long day
big day —a day on which important things happen: Today
is going to be a big day for local athletes.
long day —
1
. a working-day of fairly lengthy duration: I
made a very long day last Friday. 2. a day perceived as lasting
unusually long (because it is boring, etc.): I was held up by
storms for three long days. 3. (biol.) a long period of light: In
most polycyclic insects long days cause continuous develop-
ment.
big deal, a • big deal
big deal, a —
1
. an important business transaction: My
brother pulled off a big deal today. I think we’re going into
business together. 2. said of smth. important : This attack
alone may not be a big deal but in combination with others
it has greater impact.
Note: 
The expression does not correlate in meaning with the
phrase great deal, a— very much; a lot: Vancouver Island has
done a great deal to support the Mainland in the past, and is
doing so at present.
big deal —is used as an ironic exclamation to say that smth.
is not important at all: “So, I can charge an evening’s enter-
tainment to business expenses.” “Oh, big deal. Carry on.”
big dog • Big Grey Dog
big dog —(UK dated sl.) a man engaged to expel unruly per-
sons from a saloon, etc.; a “chucker-out”: He was “big-dog”
to a disorderly house, and when called upon … to turn out of
the establishment those who had been robbed in it he did not
do his spiriting gently.