GregOr 41 35.4.5 :ܘܠܐܒܪܗܡ ܗ݀ܘ ܕܥܣܪܝܢ ܘܚܕ܃ ܕܒܪܝܫܘܬ ܐܒܗܘܬܐ ܡܫ݁ܒܚ‏ : for Abraham, the twenty-first (descendant), he who is praised as the chief patriarch
See the entire entry for ˀabbāhū, ˀabbāhūṯā n.f. fatherhood