A card combination allowing declarer to finesse either opponent for a missing honour.
For example:
With the above card combination, you have the choice of finessing either opponent for the missing queen.
When you have a two-way finesse, you usually want to delay playing the suit. This is partly in the hope that the opponents may lead it first and partly so you can obtain as much information as possible before you have to decide who is more likely to hold the missing honour.