What does sterile mean?

• A. Free from all living microorganisms.
• B. Containing non-pathogenic bacteria.
• C. Free from viruses.
• D. Clean but not necessarily germ-free.

Answer: (A)

Sterile means free from all living microorganisms. In medical and lab settings, something sterile has been treated to kill or remove every viable microbe, including bacteria, fungi, spores, and viruses. This is stricter than being clean or sanitized, which only reduces dirt or some microbes.

If a item contains non-pathogenic bacteria, it isn’t sterile because there are living organisms present. Being free from viruses isn’t enough on its own because other microorganisms could still be present. And “clean but not germ-free” describes cleanliness rather than true sterility.