1. plural of brightness; the quality or state of being bright; luminosity or radiance
2. plural of brightness; intelligence or mental acuity
3. plural of brightness; cheerfulness or liveliness

Examples

• The different brightnesses of the stars helped astronomers classify them.
• She adjusted the brightnesses of her computer monitors for better viewing.
• The children’s brightnesses shone through their eager questions.
• Various brightnesses of LED bulbs are available at the store.
• The teacher was impressed by the brightnesses displayed by her students.
• The photographer compared the brightnesses in different areas of the image.