Provides force with crossing when laying siege (7)
I believe the answer is:
affords
'provides' is the definition.
(affording is a kind of providing)
'force with crossing when laying siege' is the wordplay.
I cannot quite see how this works, but
'force' could be 'f' (symbol used in Physics e.g. f=ma) and 'f' is found within the answer.
'crossing' could be 'ford' (ford is a kind of crossing) and 'ford' is present in the answer.
'when' could be 'as' and 'as' is located in the remaining letters.
No letters remain.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for affords that I've seen is " Gives".)