The Collaborative International Dictionary of English v.0.48:

Coigne \Coigne\ (koin), n. [See Coin, n.]
   A quoin.
   [1913 Webster]

         See you yound coigne of the Capitol? yon corner stone?
                                                  --Shak.
   [1913 Webster] Coigne

The Collaborative International Dictionary of English v.0.48:

Coigne \Coigne\, Coigny \Coign"y\, n.
   The practice of quartering one's self as landlord on a
   tenant; a quartering of one's self on anybody. [Ireland]
   --Spenser.
   [1913 Webster]

WordNet (r) 3.0 (2006):

coigne
    n 1: expandable metal or wooden wedge used by printers to lock
         up a form within a chase [syn: quoin, coign, coigne]
    2: the keystone of an arch [syn: quoin, coign, coigne]