urethrometer

u·re·throm·e·ter

(yū'rē-throm'ĕ-tĕr),
An instrument for measuring the caliber of the urethra.
[urethro- + G. metron, measure]

urethrometer

(ū-rē-thrŏm′ĕt-ĕr) [Gr. ourethra, urethra, + metron, measure]
An instrument for measuring the diameter of the urethra or the lumen of a stricture.