The form gaciaus is a cross reference to the following entry:
Despite formal similarity with Middle English washel n. (‘water source used for bathing’) and consequently Latin washellus (‘watercourse, stream, pool’, DMLBS 3733c), a connection between these forms and wassel has not been suggested (see DEAF), although some influence cannot be excluded. The apparent Middle English equivalent, borrowed from Anglo-Norman, is, with a change of suffix, gasein n. (‘slough, bog, puddle’).
A diminutive form, not attested in Anglo-Norman, is listed in DMF gacelet ('small marsh'; see also Gdf gacelet 4,199b) and T-L gascelet 4,198). The form wachas ('marsh', Gdf 8,319a) may also be related.
[KJ]