# COB

/ˈkɑb/ (US) · /kˈɒb/ (UK) · CEFR B2 · Noun

Source: https://englishreference.com/word/cob
Updated: 2026-05-11

## Definition

Stands for Close of Business. The end of the working day, usually when you need to finish a task or send an email.

For teachers: Abbreviation for Close of Business. Refers to the end of the standard working day, typically used as a deadline for deliverables or communications.

## Examples

- 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 notes

- Typically used in business contexts as a prepositional object (by COB) or as a temporal marker.

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