then
noun
that time; that moment
“we will arrive before then”
“we were friends from then on”
adjective
at a specific prior time
“the then president”
adverb
subsequently or soon afterward (often used as sentence connectors)
“then he left”
“go left first, then right”
in that case or as a consequence
“if he didn't take it, then who did?”
“keep it then if you want to”
at that time
“I was young then”
“prices were lower back then”
Source: WordNet 3.1, Princeton University