1 [intransitive and transitive]
to walk or travel, usually for a long time, with no clear purpose or direction [↪ wander]
roam over/around/about etc
The dogs are allowed to roam around.
Chickens and geese roam freely in the back yard.
You shouldn't let your children roam the streets.
roam the countryside/desert/forests etc
Wild sheep roam the hills.
2 [intransitive always + adverb/preposition, transitive]
if your eyes roam over something, you look slowly at all parts of it:
Her eyes roamed the room.
His eyes roamed over the bookshelves.