Instrument area with flashing light around LA (9)
I believe the answer is:
astrolabe
'instrument' is the definition.
(astrolabe is a kind of instrument)
'area with flashing light around la' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'with' means one lot of letters go next to another.
'flashing light' becomes 'strobe' (I've seen this before).
'around' means one lot of letters goes inside another.
'strobe' going around 'la' is 'strolabe'.
'a'+'strolabe'='ASTROLABE'
(Other definitions for astrolabe that I've seen before include "Astronomical instrument of former times" , "Navigational device" , "Early astronomical instrument" , "Old instrument for astronomical measurements" , "Old navigation instrument" .)