A lien is a specific form of security interest which is given to a particular entity or individual in order to secure some kind of payment. A lien might be given, for example, to a car mechanic who fixed another individual's car, if that other individual then refused to pay the mechanic.
The lien, in this case, would likely be given on the car itself, and it would mean that the car mechanic would have some element of property rights to the care. Lien on property, then, in general means that the holder of the lien has rights to the property, particularly in terms of selling that property in order to make up the money lost in the transaction.
One common form of a lien on property is that of a tax lien, which a lien on a particular piece of property is in order to secure the owner's payment of taxes. Tax lien properties are put under a lien by the government that was performing the taxation, in order to make the property owner pay the taxes.
Tax lien properties are different from regular properties; however, as tax liens actually travel with the property upon which the lien is placed. This is different from many other forms of lien, particularly in terms of a lien on property which is personal property and not real property. Tax lien properties, thus, will retain their liens if they change hands, meaning that the new owners of these tax lien properties will have to pay for the liens.