reflect + -ion

source: MRW I'm waiting for someone and I see a reflection of myself - GIF on Imgur

1. the throwing back by a body or surface of light, heat, or sound without absorbing it:

(光･熱･音などの)反射, 反響

e.g. the reflection of light.

an amount of light, heat, or sound that is reflected by a body or surface:

反射光, 熱

e.g. the reflections from the streetlights gave us just enough light.

an image seen in a mirror or shiny surface:

(鏡や水面などに映る)映像, 姿

e.g. Marianne surveyed her reflection in the mirror.

a thing that is a consequence of or arises from something else:

反映, 影響, 現れ

e.g. a healthy skin is a reflection of good health in general.

in singular a thing bringing discredit to someone or something:

〖単数形で〗 «…にとっての» 悪いことの現れ; 不名誉(な事), 非難 «on»

e.g. it was a sad reflection on society that because of his affliction he was picked on.

2. serious thought or consideration:

«…についての» 熟慮, 熟考, 考察; 内省

e.g. he doesn't get much time for reflection.

an idea about something, especially one that is written down or expressed:

C｟かたく｠;〖通例～s〗 (熟考の末の)意見, 考え, 感想 «on» .

e.g. reflections on human destiny and art.

3. 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.

late Middle English: from Old French reflexion or late Latin reflexio(n-), from Latin reflex- ‘bent back’, from the verb reflectere.