Correct spelling for the English word "Killow" is [kˈɪlə͡ʊ], [kˈɪləʊ], [k_ˈɪ_l_əʊ] (IPA phonetic alphabet).
An earth of a blackish or deep-blue colour; probably another name for killas.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.