Run steamship across North American lake (6)
I believe the answer is:
series
'run' is the definition.
(both can mean a sequence of things)
'steamship across north american lake' is the wordplay.
'steamship' becomes 'ss' (nautical abbreviation).
'across' indicates putting letters inside.
'north american lake' becomes 'erie' (I've seen this in another clue).
'ss' enclosing 'erie' is 'SERIES'.
(Other definitions for series that I've seen before include "See 8" , "Cycle" , "Group of related radio/TV programmes" , "Course" , "Number of similar things arranged in order" .)