Vessel showing the way to many (4)
I believe the answer is:
dhow
'vessel' is the definition.
(dhow is a kind of vessel)
'the way to many' is the wordplay.
'the way' becomes 'how' (how something is done).
'to' says to put letters next to each other (I've seen this in other clues).
'many' becomes 'D' (Roman numeral for 500).
'how' after 'd' is 'DHOW'.
'showing' is the link.
(Other definitions for dhow that I've seen before include "Type of boat used in the Indian ocean" , "Arab sailing vessel" , "Arab coastal vessel" , "Arabian sailing vessel" , "Arab lateen-rigged sailing ship" .)