Which form means stone or calculus?

• A. Glyc/o
• B. Lith/o
• C. Thym/o
• D. Histo/o

Answer: (B)

Lith/o denotes stone or calculus, coming from the Greek lithos meaning stone. It appears in terms for stones in the body—nephrolithiasis (kidney stones), urolithiasis (urinary tract stones), cholelithiasis (gallstones)—and in procedures like lithotripsy, which means crushing stones. That makes lith/o the correct form for the meaning “stone or calculus.”

The other forms don’t fit: glyc/o means sugar (as in glycemia or glycogen), thym/o refers to the thymus gland (or, in some contexts, mind), and hist/o means tissue (as in histology).