It's held to dispel gloom (5)
I believe the answer is:
torch
'dispel gloom' is the definition.
I can't tell whether this definition defines the answer.
'it's held' is the wordplay.
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'held' becomes 'orch' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
't'+'orch'='TORCH'
'to' is the link.
Can you help me to learn more?
(Other definitions for torch that I've seen before include "A large candle" , "Small hand-held battery lamp" , "source of illumination" , "Deliberately set fire to" , "Source of light" .)