Purdah is a word much in the British news at the moment. The prime minister wants to lift the so-called purdah rules, which ban the government, politicians and other interested parties from commenting or making pronouncements before the EU referendum. The word purdah comes ultimately, via Urdu, from the Persian parda, meaning a curtain. The OED defines it thus: “A curtain; esp. one used in some Muslim and Hindu communities to screen women from public observation and particularly from the sight of men or strangers. Now freq. in extended use”. The first citation in the Dictionary, dating from 1621, refers to a commercial deal concerning a “parda or peece of tapestrye, 300 rupes”.
According to the OED, purdah is also “all-enveloping clothing, especially in the form of a long veil”, “a kind of striped cotton cloth”, and also “the practice of remaining secluded from certain sections of society, ......... especially by means of a curtain or partition”. In extended use, purdah means “seclusion, isolation, secrecy”. A 1992 citation is “February is the month for pre-Budget speculation. The Chancellor retreats into purdah, and everyone tries to guess what he will announce”. The Dictionary notes that this refers “to the tradition (abolished in 1993) that in the period during which a budget statement was being prepared the Chancellor of the Exchequer might not answer questions relating to it”.
The word purdah has been well assimilated into English, with the form purdahed also in the OED.