DeMundo 146:8 :ܡܢܗܘܢ ܕܝܢ ܕܝܠܗܘܢ ܕܙܘ̈ܥܐ ܗ݀ܢܘܢ ܡ݁ܢ ܕܠܚܕ ܣܛܪ ܡܪܥܠܝܢ ܒܓܘ̈ܢܝܬܐ ܚܪ̈ܝܦܬܐ ܡܬܩܪ̈ܝܢ ܙܘ̈ܥܙܥܢܐ‏ : those quakes then that shake with sharp angles to one side are called z'
See the entire entry for zwˁzˁn adj. violently shaking