Source : Webster's Revised Unabridged Dictionary (1913)

   {Queen conch} (Zo["o]l.), a very large West Indian cameo
      conch ({Cassis cameo}). It is much used for making cameos.
      

   {Queen consort}, the wife of a reigning king. --Blackstone.

   {Queen dowager}, the widow of a king.

   {Queen gold}, formerly a revenue of the queen consort of
      England, arising from gifts, fines, etc.

   {Queen mother}, a queen dowager who is also mother of the
      reigning king or queen.

   {Queen of May}. See {May queen}, under {May}.

   {Queen of the meadow} (Bot.), a European herbaceous plant
      ({Spir[ae]a Ulmaria}). See {Meadowsweet}.

   {Queen of the prairie} (Bot.), an American herb ({Spir[ae]a
      lobata}) with ample clusters of pale pink flowers.

   {Queen pigeon} (Zo["o]l.), any one of several species of very
      large and handsome crested ground pigeons of the genus
      {Goura}, native of New Guinea and the adjacent islands.
      They are mostly pale blue, or ash-blue, marked with white,
      and have a large occipital crest of spatulate feathers.
      Called also {crowned pigeon}, {goura}, and {Victoria
      pigeon}.

   {Queen regent}, or {Queen regnant}, a queen reigning in her
      own right.

   {Queen's Bench}. See {King's Bench}.

   {Queen's counsel}, {Queen's evidence}. See {King's counsel},
      {King's evidence}, under {King}.

   {Queen's delight} (Bot.), an American plant ({Stillinqia
      sylvatica}) of the Spurge family, having an herbaceous
      stem and a perennial woody root.

   {Queen's metal} (Metal.), an alloy somewhat resembling pewter
      or britannia, and consisting essentially of tin with a
      slight admixture of antimony, bismuth, and lead or copper.
      

   {Queen's pigeon}. (Zo["o]l.) Same as {Queen pigeon}, above.
      

   {Queen's ware}, glazed English earthenware of a cream color.
      

   {Queen's yellow} (Old Chem.), a heavy yellow powder
      consisting of a basic mercuric sulphate; -- formerly
      called {turpetum minerale}, or {Turbith's mineral}.

Regent \Re"gent\ (r?"jent), a. [L. regens, -entis, p. pr. of
   regere to rule: cf. F. r['e]gent. See {Regiment}.]
   1. Ruling; governing; regnant. ``Some other active regent
      principle . . . which we call the soul.'' --Sir M. Hale.

   2. Exercising vicarious authority. --Milton.

   {Queen regent}. See under {Queen}, n.

Source : WordNet®

queen regent
     n : a queen who serves as ruler when the king cannot