noun

• (aviation) 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.
• (skiing, slang) A ski.
  "I never got down that hill without losing at least one of my skis! Clarence didn't lose his slats. The straps went over his boots and held them in place. If he fell, he risked breaking a foot or leg, but the slats stayed on."

verb

• (of rain or other water) To fall; to beat (against something).
  "[…] sending solid grey water slatting against her wheelhouse windows."
• (British, dialectal) To split; to crack.
  "Both head-peeces and habergeons were slat and dashed a peeces."