IshGen 192:26 :ܪ̈ܗܛܐ܃ ܐܓܘ̈ܓܐ ܐܘ݁ ܥܪ̈ܒܐ ܕܒܢܝܢ ܡ݂ܢ ܛܝܢܐ ܥܠ ܦܘܡ ܒܪܐ‏ : r'-troughs are channels or troughs they make out of clay on the mouth of the well
See the entire entry for ˁăreḇ, ˁarḇā n.f. vessel, bowl