business.

Syllabification: (busi·ness)
Pronunciation: /ˈbiznis/

Definition of business
noun
1a person’s regular occupation, profession, or trade:
she had to do a lot of smiling in her business
are you here on business?
an activity that someone is engaged in:
what is your business here?
a person’s concern:
this is none of your business
the neighbors make it their business to know all about you
work that has to be done or matters that have to be attended to:
government business
let’s get down to business
2the practice of making one’s living by engaging in commerce:
the world of business
whom do you do business with in Manila?
the jewelry business
[as modifier]:
the business community
trade considered in terms of its volume or profitability:
how’s business?
a commercial house or firm:
a catering business
3 [in singular] informal an affair or series of events, typically a scandalous or discreditable one:
they must be told about this blackmailing business
informal a group of related or previously mentioned things:
use carrots, cauliflower, and broccoli, and serve the whole business hot
4 Theater actions other than dialogue performed by actors:
a piece of business
5 informal a scolding; harsh verbal criticism:
the supervisor really gave him the business

Phrases

business as usual
an unchanging state of affairs despite difficulties or disturbances:
apart from being under new management, it’s business as usual in the department
have no business
have no right to do something or be somewhere:
he had no business tampering with social services
in business
operating, especially in commerce:
they will have to import from overseas to remain in business
informal able to begin operations:
if you’ll contact the right people, I think we’ll be in business
in the business of
engaged in or prepared to engage in:
I am not in the business of making accusations
like nobody's business
informal to an extraordinarily high degree or standard:
these weeds spread like nobody’s business
mean business
be in earnest.
mind one's own business
refrain from meddling in other people’s affairs:
he was yelling at her to get out and mind her own business
send someone about his/her business
dated tell someone to go away.

Origin:
Old English bisignis(see busy, -ness). The sense in Old English was 'anxiety'; the sense 'the state of being busy' was used from Middle English down to the 18th century, but is now differentiated as busyness. The sense 'an appointed task' dates from late Middle English, and from it all the other current senses have developed