JSmem 11:164 :ܒܙܒܢ ܥܘ݂ܠܐ ܘܒܬܪ ܩܠܝܠ ܐܦ ܝܠܘܕܐ܃ ܘܗܝܕܝܢ ܛܠܝܐ ܘܗܘܐ ܥܠܝܡܐ ܡܫܘܚܬܐ ܕܐܪܒܥ‏ : once an infant, after a little still a child, then a lad, and then a youth is the fourth stage
See the entire entry for mušḥā, mšuḥṯā (mušḥṯā) n.f. measure