Lines containing nothing that amuses me (3)
I believe the answer is:
lol
'amuses me' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'lines containing nothing' is the wordplay.
'lines' becomes 'll' (two abbreviations for line).
'containing' means one lot of letters goes inside another.
'nothing' becomes 'O' (looks like zero - 0).
'll' placed around 'o' is 'LOL'.
'that' is the link.
Can you help me to learn more?
(Other definitions for lol that I've seen before include "so funny online!" , "Very funny (1)" .)