She believed that she was an 'instrument' of God. [=she believed that God was using her to do things; she believed that God was acting through her]
Part of her training as a pilot involved learning to fly by 'instruments'. [=learning to fly only by looking at the instruments in the airplane]
Movies can be useful 'instruments' of social change. [=movies can be used to cause social change]
(..) What the hell is that? How is he? How are we gonna get that off of him? - How are we gonna get it off? - Let me get some instruments. Oh, God. All right. I'll make an incision here. - I'll try and remove one of the digitals from... (..)1979 Alien