1. A single-celled microorganism belonging to the domain Archaea, characterized by a distinct cell structure and ability to thrive in extreme environments such as hot springs, salt lakes, and deep-sea vents.
Usage: scientific/technical term; also called archaeon (singular) or archaea (plural); formerly classified as bacteria but now recognized as a separate domain of life

Examples

• Archaebacteria were discovered in extreme environments where most other life forms cannot survive.
• Scientists study archaebacteria to understand the origins of life on Earth.
• Some archaebacteria produce methane gas as a byproduct of their metabolism.
• The cell membranes of archaebacteria differ significantly from those of true bacteria.
• Archaebacteria found in hot springs can withstand temperatures above 100 degrees Celsius.