A business day is considered every official working day of the week. Another common term is working day. Typically, these are the days between and including Monday to Friday and do not include public holidays and weekends.
The definition of a business day varies by region. It depends on the local workweek which is dictated by local customs, religions, and business operations. For example, in the United States and much of the Western world, they are typically Monday to Saturday. Within the EU the normal business days are Monday to Saturday based on the working time regulation of the EU.
Business days are commonly used by couriers when determining the arrival date of a package. If courier ships a parcel on a Thursday that will be delivered in "two business days", it will arrive on the following Monday (if neither Friday nor Monday are a holiday).
In finance, how business days are defined are called "business day conventions" and determine how payments are settled on contracts such as interest rate swaps.
Shifts and trends
The introduction of flex time introduces the internet as a more easily globalized and offshored workforce. The notion of a business day has come under a certain degree of challenge. Information-based companies with a limited dependence on physical goods have less of a need to distinguish a weekend day from a weekday and indeed to many, there is no difference at all. These companies, quite validly, construe a business day to be any day on which they provide service.
Some businesses conduct business transactions and operations on a 24/7 basis due to the nature of the field. Such businesses include hotels, hospitals, police and fire departments, gas stations and airports.