billfold vs pin

billfold

noun
  • A small, folding sleeve or case designed to hold paper currency, as well as credit cards, pictures, etc. 

pin

noun
  • A simple accessory that can be attached to clothing with a pin or fastener, often round and bearing a design, logo or message, and used for decoration, identification or to show political affiliation, etc. 

  • A piece of jewellery that is attached to clothing with a pin. 

  • The spot at the exact centre of the target, originally a literal pin that fastened the target in place. 

  • A cylinder often of wood or metal used to fasten or as a bearing between two parts. 

  • Any of the individual connecting elements of a multipole electrical connector. 

  • The flagstick: the flag-bearing pole which marks the location of a hole 

  • A peg in musical instruments for increasing or relaxing the tension of the strings. 

  • A thing of small value; a trifle. 

  • A size of brewery cask, equal to half a firkin, or eighth of a barrel. 

  • A pinball machine. 

  • One of a row of pegs in the side of an ancient drinking cup to mark how much each person should drink. 

  • The spot at the exact centre of the house (the target area) 

  • A short shaft, sometimes forming a bolt, a part of which serves as a journal. 

  • The victory condition of holding the opponent's shoulders on the wrestling mat for a prescribed period of time. 

  • A needle without an eye (usually) made of drawn-out steel wire with one end sharpened and the other flattened or rounded into a head, used for fastening. 

  • Either a scenario in which moving a lesser piece to escape from attack would expose a more valuable piece to being taken instead, or one where moving a piece is impossible as it would place the king in check. 

  • The tenon of a dovetail joint. 

  • A small cylindrical object which blocks the rotation of a pin-tumbler lock when the incorrect key is inserted. 

  • A small nail with a head and a sharp point. 

  • A slender object specially designed for use in a specific game or sport, such as skittles or bowling. 

  • A leg. 

verb
  • To attach (an icon, application, message etc.) to another item so that it persists. 

  • To cause an analog gauge to reach the stop pin at the high end of the range. 

  • To enclose; to confine; to pen; to pound. 

  • To fix (an array in memory, a security certificate, etc.) so that it cannot be modified. 

  • To cause (a piece) to be in a pin. 

  • To pin down (someone). 

  • To fasten or attach (something) with a pin. 

How often have the words billfold and pin occurred in a corpus of books? (source: Google Ngram Viewer )