COB
n. uncountable B2 Upper Intermediate US //ˈkɑb// UK //kˈɒb// cob
n. Stands for Close of Business. The end of the working day, usually when you need to finish a task or send an email.
n. Abbreviation for Close of Business. Refers to the end of the standard working day, typically used as a deadline for deliverables or communications.
Please send me the report by COB today.
The manager requested that all team members submit their weekly timesheets by COB on Friday to ensure payroll processing.
While the official deadline is COB, the global nature of the team means that 'end of day' often extends until the final regional office closes its doors.
Usage
Typically used in business contexts as a prepositional object (by COB) or as a temporal marker.