Kays 208:18 :ܕܝܡܐܛܪܘܢ ܕܐܝ݂ܬܘܗܝ ܕܠܩܘ݂ܒܠܝܘ݂ܬܐ ܕܗ݀ܘܐ ܒܝܢܬܗܘܢ ܦܠܓܗ݀ ܕܡܘܙܠܬܐ‏ : d' is opposition when there is half the cosmic sphere between them
See the entire entry for dīameṭrōn, dīameṭrōs n.m. diameter