calculus
A small, hard mass or stone formed in the body, as in a kidney or gallbladder, or a hard coating on the surface of the teeth.
Last Updated
October 7, 2025
October 7, 2025
Last updated: October 7, 2025.
This article was contributed by .
Explore More
Vaccine Facts: What You Need to Know
It can be hard to know what to believe about vaccines. There’s a lot of information out there—especially in the age of social media—and not all of it is accurate. Having clear, trustworthy facts ca...