REDDENDUM
Etymology
Noun
reddendum (plural reddendums or reddenda)
(legal) A clause in a deed by which some new thing is reserved out of what had been granted before; the clause by which rent is reserved in a lease.
Source: Wiktionary
Red*den"dum (rd*dn"dm), n. Etym: [Neut. of L. reddendus that must be
given back or yielded, gerundive of reddere. See Reddition.] (Law)
Definition: A clause in a deed by which some new thing is reserved out of
what had been granted before; the clause by which rent is reserved in
a lease. Cruise.
Source: Webster’s Unabridged Dictionary 1913 Edition