10ac Soft silvery-whie metalic element of the alkali group that ignites spontaneeously in air; used in photocells and vacujum-tube filaments. (8) (r?b?/i?m) 11ac Soft white sheep or c ow`s milk cheese commonly used in dishes such as ravioli and gnoccik; literally,`recooked` (7) (r??o???) 15ac Metric unit of mass equal to 15.432 grains or approximately o.o35 ounces. (4) (g???) 17acDerived Si unit of pressure equal to one newton per square metre. (6) (???c??)