A thing to bear from one side to the other (6)
I believe the answer is:
across
'from one side to the other' is the definition.
(I've seen this in another clue)
'a thing to bear' is the wordplay.
I cannot quite understand how this works, but
'a' is within the answer.
The remaining letters 'cross' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for across that I've seen before include "From side to side of (something)" , "what follows one here" , "this venue" , "Clue with solution not going in the direction of this one!" , "First word in any crossword" .)