Which combining form means stone or calculus?

• A. Lith/o
• B. Glyc/o
• C. Hidr/o
• D. Lacrim/o

Answer: (A)

Stone is conveyed by the combining form lith/o. The term lithos is Greek for stone, and in medical language this root appears in words like nephrolithiasis (kidney stone), cholelithiasis (gallstone), and lithotripsy (procedure to crush stones). Because calculus refers to a stone, lith/o is the form that means stone or calculus.

Glyc/o means sugar, leading to terms about glucose or glycogen. Hidr/o relates to sweat, seen in conditions like hidradenitis. Lacrim/o relates to tears, as in lacrimal. These do not denote stone, so they don’t fit the prompt.