Mapping instrument? (3)
I believe the answer is:
pin
'instrument?' is the definition.
(thesaurus)
'mapping' is the wordplay.
'PIN' is hidden in amongst the letters.
However, I am uncertain how the hidden word is indicated.
Can you help me to learn more?
(Other definitions for pin that I've seen before include "Fastener; brooch" , "Needle" , "Small brooch; skittle" , "Skittle; chess attack" , "Peg or nail" .)