jə̇ˈrärd- noun
or gi·rard's reagent -dz-
Usage: usually capitalized G
Etymology: after André Girard, 20th century French chemist
: any of several hydrazides that contain a quaternary ammonium radical and are useful especially in separating aldehydes or ketones (as some steroid hormones) from mixtures by forming soluble hydrazones: as
a. : a crystalline compound (CH 3 ) 3 N(Cl)CH 2 CONHNH 2 derived from trimethylamine or betaine — called also Girard T reagent
b. : a crystalline compound C 5 H 5 N(Cl)CH 2 CONHNH 2 derived from pyridine — called also Girard P reagent