Longman Dictionary of Contemporary English - then

~1 adv 1 at a particular time in the past or future  (It was then that I realised she'd tricked me. | I used to go to school with Mavis Butterwick, or Mavis O'Brien as she then was. | The furniture is being delivered next week so until then we'll have to sit on the floor. | from then on (=starting at that time))  (They met in 1942 and from then on they were firm friends. | just then)  (Silently she closed the door. Just then she heard a noise. | back then (=a long time ago in the past, when things were different))  (Back then we spent holidays in Blackpool. | then and only then)  (Tidy your room, then and only then can you go out with Mike.) 2 next; after something has happened  (You're doing it all wrong. Mix the flour and butter and then add the eggs. | First the passengers and then the stewards jumped from the wreckage.) 3 used to say that because of what you know about the situation, something else is probably true  (Still in your pyjamas? Have you just got out of bed then? | if...then...)  (If x =3 and y =5 then xy =15 .) 4 but then (again) especially spoken used to say that although something is true something else is also true which makes the first thing seem less important  (I don't spend much but then I don't really go out much.) 5 spoken used at the end of questions, statements etc, especially to agree with someone or to make people aware that you are speaking  (So, what do you do then? | Right then, shall we start? | "Mom, will you play tennis with me?" "Get the balls out then.") 6 especially spoken used when giving your opinion or advice about something  (If you're going to go then go. | "He's boring, rude and arrogant." "Then divorce him.") 7 so that something happens or so that someone does something  (Wear a big hat and dark glasses then no one will recognize you.) 8 used in a list of things when you have remembered something else you want to add  (I do all the washing and cleaning and then there's the ironing too.) 9 then and there also there and then immediately  (I expected to have to wait a few days, but they issued the passport then and there.)  (- see also now and then now1 (6)) ~2 adj the then President, Director etc the President, Director etc at a particular time in the past  (secretary to the then Head of Light Entertainment)