* At that time; afterward: This is the most frequent usage. It refers to a point in time following a previously mentioned event or time. Example: "I went to the store, and *then* I went home."
* In that case; consequently: This usage indicates a result or consequence. Example: "If you're tired, *then* you should rest."
* Next; afterward (in a sequence): This shows the order of events. Example: "First, we'll eat; *then*, we'll go for a walk."
* At another time: This implies a different point in time, often contrasting with the present. Example: "I was happy *then*, but I'm not so sure now."
The meaning is usually clear from the surrounding sentence.