''a se duce'' to go ''a merge'' to walk

"A se duce" - it is an unidirectional verb. It is equal to "to go to...". Ex. "Mă duc acasă." - "I am going home." "A merge" - is pluridirectional. It is equal both with "to go to" and simply "to walk". Ex. "E timpul să merg acasă." - "It's time to go home." ; "Merg pe stradă." - "I am walking on the street."

Roxana explained well. We use "a se duce" when we want to get to a place. "Ma duc in parc." If I want to say that I'm walking in the park, I say "Merg (ma plimb) prin parc." :)

One more thing. One is "a duce ceva"(to carry smth, to bear smth) and another one is the reflexive form of the verb "a se duce undeva" (to go somewhere).

There are countless definitions for both of them. I guess "a se duce" is more like to go and "a merge" is more like to walk. A specific context would make it easier to explain their meaning.