verb

• (transitive) To encircle something or simultaneously extend in all directions.
  "The hovel stood in the centre of what had once been a vegetable garden, but was now a patch of rank weeds. Surrounding this, almost like a zareba, was an irregular ring of gorse and brambles, an unclaimed vestige of the original common."
• (transitive) To enclose or confine something on all sides so as to prevent escape.
  "The lions surrounded the deer herd so they had no way to escape."
• (transitive, obsolete) To pass around; to travel about; to circumnavigate.
  "to surround the world"

noun

• (British) Anything, such as a fence or border, that surrounds something.
  "He drifted through the room, avoiding the furniture by instinct, closed the door that led to the passage, and only then flicked on his flashlight. It swept around the room, picking out a desk, a telephone, a wall of bookshelves, and a deep armchair, and finally settled on a handsome fireplace with a large surround of red brick."