Lenses refract light.
Concave: Lens caves inwards, the parallel light rays are spread out (diverge)
Convex: Lens caves outwards, the parallel light rays are brought together at a principle focus point (Converge)
When describing an image you have to say if it's: upside down, how big it is compared to the real object, and wether it's real or virtual.
Virtual image is not the direct object but looking at an object using something, e.g a mirror or a magnifying glass.