1 [mass noun] the throwing back by a body or surface of light, heat, or sound without absorbing it:the reflection of light
[count noun] an amount of light, heat, or sound that is reflected by a body or surface:the reflections from the street lamps gave them just enough light
[count noun] an image seen in a mirror or shiny surface:Marianne surveyed her reflection in the mirror
[count noun] a thing that is a consequence of or arises from something else:a healthy skin is a reflection of good health in general
[in singular] a thing bringing discredit to someone or something:it was a sad reflection on society that because of his affliction he was picked on
2 [mass noun] serious thought or consideration:he doesn’t get much time for reflection
[count noun] an idea about something, especially one that is written down or expressed:reflections on human destiny and art
3 [count noun] Mathematics the conceptual operation of inverting a system or event with respect to a plane, each element being transferred perpendicularly through the plane to a point the same distance the other side of it.