† ˈunder-ˌthesaurerObs. [under-1 6 a.] An under-treasurer. 1534Cromwell in Merriman Life & Lett. (1902) I. 373 Suche patenttes and grauntys as your highnes and..your father..haue grauntyd vnto..your undertesawrer of your exchequer.1536–7Act in Bolton Stat.Irel. (1621) 104 So as the said underthesaurer be one.