noun, counter
business day; working day
Refers to a day when a business or office is open. Also used as a counter for the number of business days.
当店の営業日は月曜日から金曜日です。
Our business days are Monday through Friday.
発送までに3営業日かかります。
It takes three business days to ship.
休業日 is the opposite: a day when a business is closed.
Compound of 営業 (business, operations) and 日 (day). The reading is the standard on'yomi combination.