A prison is a facility built for the purpose of confining sentients against their will. Utilized across the galaxy by various governments and organizations, ostensibly, this is a penal institution in which the individuals are being detained as a punishment for a crime they have committed, or while awaiting trial. Many organizations use the prisons for rehabilitation and keep the prisoners well kept and educated in hopes of reintegrating them into society. Others generally torture and malnourish their prisoners, with some even offering prisoners as slaves to create additional revenue.
Prisons have myriad different designs, ranging from a few simple cells made of thick and sturdy walls and doors, to duracrete and transparisteel fortresses containing deadly traps, energy shields, and gun emplacements. Nearly every facility will have guards of some type to monitor the residents, and many have the means to accommodate prisoners with varying survival requirements according to species.