A last stand is a loose military term used to describe a body of troops holding a defensive position in the face of overwhelming odds. The defensive force usually takes very heavy casualties and on occasion is completely destroyed.
The situation can arise in one of two ways. Sometimes, the troops in question cannot retreat from their position without being destroyed by the enemy. At other times, the troops in question are following orders and refuse to retreat even though the option is open to them. In both cases, surrender is an option but the group as a whole decides instead to go down fighting.
A siege will often lead to a last stand by the defenders of the besieged city. However, while sieges are generally characterised by a lengthy engagement, last stands are generally short and decisive.
Famous examples of last stands include: