Definition

Noun: - Phosphorescence; luminescence: A type of light that glows in the dark, often with a greenish or bluish hue, emitted by certain substances after absorbing light energy. It does not produce heat like incandescence. - (In specific contexts) A substance or material that exhibits this property: A material coated with or containing phosphors that glow in the dark.

Usage Examples

• Noun:
  • Đồng hồ có kim dạ quang rất tiện lợi khi xem giờ ban đêm. (A watch with luminous hands is very convenient for telling time at night.)
  • Một số sinh vật biển có khả năng phát dạ quang. (Some marine creatures have the ability to emit bioluminescence.)
  • Cô ấy dán những ngôi sao dạ quang lên trần nhà. (She stuck glow-in-the-dark stars on the ceiling.)

Advanced Usage

• "Dạ quang" as an attributive noun: Often used before another noun to describe an object that glows in the dark.
  • sơn dạ quang (luminous paint / glow-in-the-dark paint)
  • đồ chơi dạ quang (glow-in-the-dark toy)

Variants and Related Words

• Phát quang (verb): To luminesce; to emit light without heat. This is the general action.
• Huỳnh quang (noun): Fluorescence. This is a related but distinct phenomenon where light is emitted only while the energy source is present (e.g., under a UV light), whereas "dạ quang" (phosphorescence) persists after the energy source is removed.
• Lân quang (noun): Another term for phosphorescence, synonymous with "dạ quang".

Synonyms

• Sự phát sáng trong bóng tối: Glowing in the dark.
• Ánh sáng lân quang: Phosphorescent light.

Related Phrases and Compounds

• Hiện tượng dạ quang (noun phrase): The phenomenon of phosphorescence.
• Chất dạ quang (noun phrase): Phosphorescent substance; phosphor.

Notes on Meaning

• Not "firefly": While some historical or poetic contexts might loosely associate "dạ quang" with the light of fireflies (đom đóm), its primary and modern meaning is the physical phenomenon of phosphorescence. The reference to "fire-fly" is likely a metaphorical or outdated translation. The core concept is an object's inherent property to store and slowly release light energy, creating a glow in darkness.
• Technical vs. Common Use: In technical contexts (physics, chemistry), it specifically means phosphorescence. In everyday language, it commonly describes commercial products (watch hands, stickers, paint) that glow in the dark.

noun

1. fire-fly; glow-worm