For the mathematical field:
* Infinitesimal analysis: This is a more formal and precise term, emphasizing the use of infinitesimals in calculus.
* Differential and integral calculus: This specifies the two main branches of calculus.
* Mathematical analysis: This broader term encompasses calculus as well as other areas of analysis.
For the small, hard stone:
* Stone: This is the most generic synonym.
* Pebble: This refers to a small, smooth stone.
* Gravel: This refers to a collection of small stones.
For the medical term:
* Kidney stone: This specifies the type of stone.
* Renal calculus: This is the medical term for a kidney stone.
* Urolithiasis: This refers to the condition of having stones in the urinary tract.
To choose the best synonym, consider the specific context and the intended meaning of the word "calculus."