Bengali: কক

[Scyl_la]

Good evening everyone,

Does anybody know what কক (followed by a number) could mean in an official document?
It looks like
কক [number]
[]DOCUMENT TITLE]

Looks like it could be easily replaced with 'No.'.
Do you have any suggestions?

Thank you!

 

[Dib]

No idea. Maybe it's a part of the document number itself (like AA123...)?