Read the dictionary definition of then. All definitions for this word.
1. that time; that moment
1. we will arrive before then
2. we were friends from then on
2. at a specific prior time
1. the then president
3. subsequently or soon afterward (often used as sentence connectors)
1. then he left
2. go left first, then right
3. first came lightning, then thunder
4. we watched the late movie and then went to bed
5. and so home and to bed
4. at that time
1. I was young then
2. prices were lower back then
3. science as it was then taught
5. in that case or as a consequence
1. if he didn't take it, then who did?
2. keep it then if you want to
3. the case, then, is closed
4. you've made up your mind then?
5. then you'll be rich