Licences come in various forms. Some have similar terms to leases, others can be simply permission to traverse a piece of land or access rights.
Licences that have similar characteristics as leases are regarded by the courts as being leases regardless of which word is written on the top of the paperwork.
As the previous poster says, leases are usually exclusive possession - normally if you were taking an entire self contained premises, whether it be part of a building or the whole building, you would probably lease. However, office blocks that let out space within a building e.g part of a floor, that is not self contained is usually by means of a license.