Projectile from lake is found in sea (9)
I believe the answer is:
ballistic
'projectile' is the definition.
(I've seen this before)
'lake is found in sea' is the wordplay.
'lake' becomes 'l'.
'found in' is an insertion indicator.
'sea' becomes 'baltic' (Baltic is an example**).
'l'+'is'='lis'
'lis' going inside 'baltic' is 'BALLISTIC'.
'from' is the link.
(Other definitions for ballistic that I've seen before include "To do with the flight of projectiles - basic lilt (anag)" , "Relating to projectiles and their flight" , "Winsome deer" , "Like missiles" , "Moved by gravity" .)