[adjective] [not gradable]Postal means relating to post or to the public service that collects and delivers the post.postal chargesthe postal servicea postal strikepostal workersPeople who cannot vote in person at the election can take part in a postal ballot (US absentee ballot) by sending in a postal vote (US and ANZ absentee vote).(esp. UK) A postal order (US usually, ANZ also money order) is a piece of paper with an amount of money written on it, which you send through the post to someone, who can then exchange it for the same amount of money at a post office.
POSTAL
Meaning of POSTAL in English
Cambridge English vocab. Кембриджский английский словарь. 2012