Burden we bear (4)
I believe the answer is:
onus
I believe this is a double definition.
'burden' is the first definition.
('onus' can be a synonym of 'burden')
'we bear' is the second definition.
(we carry anything on us)
(Other definitions for onus that I've seen before include "Burden, duty" , "albatross?" , "Obligation - charge" , "Encumbrance" , "Weight of responsibility" .)