Definition of yours faithfully in US English:

yours faithfully

phrase

British
  • A formula for ending a formal letter to someone whose name you do not know.

    • ‘We write ‘yours sincerely’ or ‘yours faithfully’ at the bottom of a letter, then fret for days about whether we chose the right one.’
    • ‘However the basic rule is that when you use Dear Sir/Madam then you end with yours faithfully.’