kopno

1. land; dry land
   Posle deset dana na brodu konačno smo na kopnu. — After ten days on the ship we're finally on land.
   Do ostrva ne može da se stigne kopnom. — You can't reach the island by land.
2. (as opposed to islands) mainland
   Ostrvo je mostom povezano s kopnom. — The island is connected to the mainland by a bridge.

The form "kopnom" means "by land": putovati kopnom.