definiendum

noun

de·​fin·​i·​en·​dum di-ˌfi-nē-ˈen-dəm 

plural definienda di-ˌfi-nē-ˈen-də 

: an expression that is being defined

Word History

Etymology

borrowed from Latin dēfīniendum "something to be defined," from neuter gerundive of dēfīnīre "to mark the limits of, determine, define"

First Known Use

1871, in the meaning defined above