Illumination

n.hopeful, thoughtfulprofessional

Meaning 1

Light provided to make a place or object visible.

Reach for it when naming the amount, quality, or arrangement of useful light

Gentle illumination from the side revealed the texture of the old map.

everyday
brightness
the strength of visible light is what matters
not when Brightness measures intensity rather than the provision of light.
everyday
lighting
fixtures or practical light design are under discussion
not when Lighting is concrete and does not carry illumination's intellectual sense.
literary
radiance
the light has a beautiful glowing quality
not when Radiance is aesthetic and may not improve visibility.

A sudden or gradual arrival of clearer understanding.

Reach for it when describing insight that brings a difficult matter into focus

The final interview brought illumination to a motive the records had missed.

professional
clarity
understanding is now orderly and precise
not when Clarity can result from editing rather than a revealing insight.
professional
insight
one penetrating understanding is being named
not when Insight is the realization itself; illumination can be the process or effect.
formal
enlightenment
the understanding is broad, transformative, or spiritual
not when Enlightenment overstates a modest explanation.

natural illumination
Natural illumination keeps the studio usable without overhead lamps.
soft illumination
Soft illumination protected the atmosphere of the evening recital.
moment of illumination
A moment of illumination came when the student redrew the problem.

The definition and the example on this page are written here. The dictionaries above ground which meaning is being described, not the wording.