The name Krypton is derived from Ancient Greek: κρυπτός (hidden), which was romanized into kryptos ('the hidden one').

Key facts out Krypton:

• Discovery: Discovered in 1898 by British chemists Sir William Ramsay and Morris W. Travers. 
• Occurrence: Found in trace amounts in Earth's atmosphere, making it a very rare gas. 
• Appearance: Colorless, odorless gas. 
• Uses: Primarily used in lighting applications like photography, airport runways, and fluorescent lights due to its ability to produce a bright white light. 
• Spectral signature: Emits a distinctive greenish-yellow glow when excited by electricity. 
• Laser technology: Krypton is also used in krypton-fluorine lasers. 
• Non-toxic but can be asphyxiant: While not considered toxic, inhaling high concentrations of krypton can cause oxygen deprivation. 

In a lighter sense, Krypton is a fictional planet appearing in American comic books published by DC Comics, most commonly appearing or mentioned in stories starring the superhero Superman as the world from whence he came. The planet was created by Jerry Siegel and Joe Shuster, and was named after the chemical element krypton, and the people from Krypton were called Kryptonians.

The word 'kryptonite' also comes to us from comic books and refers to a mineral from the planet Krypton.  In its best-known form, Kryptonite is a green, crystalline material that is capable of emitting a unique, poisonous radiation that can weaken and even kill Kryptonians, including Superman.  Kryptonite radiation can be transmitted through any element/material except lead.

Just the facts:

Krypton Definition & Meaning - Merriam-Webster