n.
      - a tool or implement, especially for precision work.
 - a measuring device, especially in a vehicle or aircraft.
 - 
(also musical instrument)
 a device for producing musical sounds.
 - a means of pursuing an aim.
 - a person who is made use of.
 - a formal or legal document.
 
v.
 equip with measuring instruments.
 
  Etymology
  ME: from OFr., or from L. instrumentum ‘equipment, implement’, from instruere ‘construct, equip’.