means Describing something that bounces back light or sound, or a person given to thoughtful, inward consideration.

from From Latin 'reflectere,' to bend back — 're-' (back) plus 'flectere' (to bend), the same bending hidden in 'flexible' and 'deflect.' The literal sense of light bending back came first; the mental sense, of thoughts turned back upon themselves, is a later borrowing of the same image.