Meaning seen to change when preceded by "S" (5)
I believe the answer is:
sense
'meaning' is the definition.
(sense is a kind of meaning)
'seen to change when preceded by s' is the wordplay.
I cannot quite see how this works, but
an anagram of 'seen' is 'ense' which is within the answer.
's' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for sense that I've seen before include "Feel, perceive" , "Perceptual faculty" , "Hearing maybe" , "Sat lazily; hung loosely" , "Nous" .)