Charm of old lady's bed (6)
I believe the answer is:
mascot
'charm' is the definition.
(synonyms)
'old lady's bed' is the wordplay.
'old lady's' becomes 'ma's' (both can informally mean mother).
'bed' becomes 'cot' (cot is a type of bed).
'mas'+'cot'='MASCOT'
'of' is the link.
(Other definitions for mascot that I've seen before include "Something bringing luck" , "Charm - talisman" , "Lucky thing" , ".Person or thing believed to bring good luck" , "Bringer of good luck to team, etc" .)