Environmentally friendly prefix

ECO

Think of the first part of words like "system" or "tourism" that focus on nature and sustainability. It’s often paired with concepts that aim to protect the planet.

The clue asks for a prefix meaning "environmentally friendly," which is a common shorthand in words like "ecology" or "economy" when discussing sustainability. "Eco" fits perfectly because it’s derived from the Greek oikos (house or environment) and appears in terms like "eco-friendly" or "ecosystem." There’s no wordplay here—it’s a straightforward definition pointing to a well-known three-letter prefix. Think of products labeled "eco" to signal they’re green or nature-conscious.