Plain English Meaning

Argon is a small but steady part of the air around us. It does not react with other things, has no color or smell, and is just there as part of the mix we breathe and fly through.

Full Definition

Argon is a colorless, odorless, chemically inert gas that makes up roughly 0.93 percent of Earth's atmosphere by volume, making it the third most abundant atmospheric gas after nitrogen and oxygen.

Context Anchor

Seen in basic atmosphere discussions, where the handbook explains what air is made of before covering pressure, temperature, and weather.

Derivation

From the Greek 'argos,' meaning 'lazy' or 'idle.' It was named this because it does not react chemically with other elements -- it just sits in the air doing nothing. That laziness is exactly why it stays a background part of the atmosphere.