What's the difference between margrave and margravine?

Margrave

Definition:

(n.) Originally, a lord or keeper of the borders or marches in Germany.
(n.) The English equivalent of the German title of nobility, markgraf; a marquis.

Example Sentences:

(1) Solicitor Clive Margrave-Jones and Financial Planners Ltd are putting together a group of individuals who have been affected by tax rules to challenge the law that allows widows and widowers but not gay partners to inherit the other partner's property free of inheritance tax.
(2) In his unfinished, posthumously published autobiography, Margrave of the Marshes , there is a photograph of John Peel "compiling the running order for his programme in his room at home".
(3) Mr Margrave-Jones, of the law firm Margraves in Llandrindod Wells, has obtained a legal opinion backing the case from Hugh Tomlinson, a leading human rights QC at Matrix, the chambers Cherie Booth QC also works from.
(4) Financial Planners Ltd are working with Mr Margrave-Jones to bring potential claimants together to share the costs of what is likely to be an expensive legal process.
(5) Mr Margrave-Jones said: "We are claiming that these people who have lived together for a long time have not been given the opportunity to register their relationship for tax purposes, which is an infringement on their human rights."

Definition:

Example Sentences:

(1) 4.06pm BST At another fringe meeting there seems to have been a lively exchange between Danny Alexande r, the chief secretary to the Treasury who led a Whitehall review of alternatives to Trident, and Lady Falkner of Margravine , co-chair of the Lib Dem backbench international affairs committee.