It's changed, but the meaning's the same (3)
I believe the answer is:
tis
'the meaning's the same' is the definition.
I can't judge whether this defines the answer.
'it's changed' is the wordplay.
'changed' is an anagram indicator.
'its' with letters rearranged gives 'TIS'.
'but' acts as a link.
Can you help me to learn more?
(Other definitions for tis that I've seen before include "That thing's" , "I confirm the identity of" , "Contraction of it is" , "It is shortened" , "Pacific trees" .)