I am trying to complete some course work which involves letter writing. Please can somebody tell me why in an old fashioned letter people wrote: eg. we are in receipt of your letter of the 13th inst. What does "inst" stand for? I can guess but it would be great to have the official reply. Thank you.
It's an abbreviation of "instant", which once had the meaning of "current". In this context it means "of the current month".