Way south lies beside bay, perhaps, west of Teignmouth (6)
I believe the answer is:
street
'way' is the definition.
(I know that street is a type of way)
'south lies beside bay perhaps west of teignmouth' is the wordplay.
'south lies' becomes 's' (I can't explain this - if you can you should give a lot more credence to this answer).
'beside' says to put letters next to each other.
'bay perhaps' becomes 'tree' (bay is a kind of tree).
'west of' indicates taking the first letters (most west - leftmost - letter).
The first letter of 'teignmouth' is 't'.
's'+'tree'+'t'='STREET'
Can you help me to learn more?
(Other definitions for street that I've seen before include "City road" , "A thoroughfare or public road" , "See 17" , "- Arab; - light" , "Perry's Della" .)