Ennoblement
In France, a seigneury might include one or more manors surrounded by land and villages subject to the noble's prerogatives and disposition. Seigneuries could be bought, sold or mortgaged. But if erected into, e.g. a barony or countship, was legally entailed for a family, who could use it as their title (although most nobles were untitled: "seigneur of Montagne" meant ownership of the lordship but not, if one was not otherwise noble, the right to use its associated title). However, any French noble who bought a countship was allowed, ipso facto, to style himself as its comte.
By contrast, in the United Kingdom royal letters patent were necessary to take a noble title, which also carried a seat in the House of Lords, but came with no automatic entail nor rights to the local peasants' output.
Quite often, however, nobility came to be associated only with specific social privileges and a general expectation of deference from those of lower rank. An example of the latter would be early 20th-century Polish nobility after their political, economic, judicial and religious privileges were abolished in 1923 and they remained only landed proprietors on the same legal basis as their commoner neighbours.
Read more about this topic: European Nobility