[ gdw]
For a more frequent synonym, see osteler1. The only Anglo-Norman attestation of this word is found here in the register of John of Gaunt, where, interestingly, it is used with reference to people working in La Roche-sur-Yon (Gascony). That no form of the word is found in English (or in the DMLBS) suggests that the term was not really current in England.