Thrown back after striking a surface; as, reflected light, heat, sound, etc.

Hence: Not one's own; received from another; as, his glory was reflected glory.

Bent backward or outward; reflexed.

(especially of incident sound or light) bent or sent back; "reflected light"; "reflected heat"; "reflected glory"

When we say something is reflected, we mean it bounces off. When light hits something (like the earth or a tree), one of the things it can do is be reflected. This means it bounces off in a new direction. When our eyes look at an object, what they actually are seeing is the light which reflects off of the object. That's why you can't see very well in a dark room: there is very little light reflecting off the objects in the room. The green arrows in the picture represent reflected sunlight.

curved or bent outwards at the edge, as in the lip of some shells