mainstay vs staff

mainstay

noun
  • A stabilising rope from the top of the mainmast to the bottom of the foremast. 

  • Someone or something that can be depended on to make a regular contribution. 

  • A chief support. 

staff

noun
  • An arbor, as of a wheel or a pinion of a watch. 

  • The grooved director for the gorget, or knife, used in cutting for stone in the bladder. 

  • A series of verses so disposed that, when it is concluded, the same order begins again; a stanza; a stave. 

  • A pole, stick, or wand borne as an ensign of authority; a badge of office. 

  • A long, straight, thick wooden rod or stick, especially one used to assist in walking. 

  • The employees of a business. 

  • A pole upon which a flag is supported and displayed. 

  • An establishment of officers in various departments attached to an army, to a section of an army, or to the commander of an army. The general's staff consists of those officers about his person who are employed in carrying his commands into execution. 

  • A mixture of plaster and fibre used as a temporary exterior wall covering.ᵂ 

  • A series of horizontal lines on which musical notes are written; a stave. 

verb
  • To supply (a business, volunteer organization, etc.) with employees or staff members. 

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