Warding is when a item/skill is placed in a certain place to grant vision and map awareness. Wards are used to prevent ganks and to know when objectives are being taken.
Skills and items that can wardEditStaff of Tinos (75 gold)
Staff of Protection (150 gold)
Vanguard Brooch (Item) (2800 gold)
Elemental Lord (Migrove)'s Bioluminescence skill
Ant Guard (Clip Dirtblade)'s Ant Sentries skill
Child of the Forest (Nuutt)'s Survival Skills skill
Goblin Scout (Khlint Giantslayer)'s Cunning Trap