A rare word in Anglo-Norman, thus far only found in this early fifteenth-century attestation. Surprisingly, no other derivatives of the Latin etymon ostendere (cf. also DMF ostendre, ostensif, ostension and ostentation) are attested in Anglo-Norman. In Middle English, the word family seems to appear over the course of the fifteenth century (cf. OED ostend v. (c.1429) and ostension n. (1474) – however, ostensor n. is attested in English from 1804, with the religious sense ‘monstrance’).