firewall: a fireproof (or fire-resistant) wall designed to prevent the spread of fire through a building or a vehicle
wall: an architectural partition with a height and length greater than its thickness; used to divide or enclose an area or to support another structure
gentiana: type genus of the Gentianaceae; cosmopolitan genus of herbs nearly cosmopolitan in cool temperate regions; in some classifications includes genera Gentianopsis and Gentianella