slat vs tranche

slat

verb
  • To split; to crack. 

  • To set on; to incite. 

  • To construct or provide with slats. 

  • To slap; to strike; to beat; to throw down violently. 

noun
  • A ski. 

  • A thin, narrow strip or bar of wood (lath), metal, or plastic. 

  • A control surface that extends forwards and downwards from the leading edge of a wing, leaving a gap between it and the leading edge, in order to modify the airflow around the wing so as to allow flight at a higher angle of attack without stalling, lowering the aircraft's stall speed. 

  • A thin piece of stone; a slate. 

tranche

verb
  • To divide into tranches. 

noun
  • A distinct subdivision of a single policyholder's benefits, typically relating to separate premium increments. 

  • One of a set of classes or risk maturities that compose a multiple-class security, such as a CMO or REMIC; a class of bonds. Collateralized mortgage obligations are structured with several tranches of bonds that have various maturities. 

  • A pension scheme's or scheme member's benefits relating to distinct accrual periods with different rules. 

  • A slice, section or portion. 

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