Reddendum
Red*den"dum\ (r?d*d?n"d?m), n. [Neut. of L. reddendus that must be given back or yielded, gerundive of reddere. See Reddition.] (Law) 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.