This book explores a key issue in linguistic theory, the systematic variation in form between semantic equivalents across languages. Two contrasting views of the role of lexical meaning in the analysis of such variation can be found in the literature: (i) uniformity, whereby lexical meaning is universal, and variation arises from idiosyncratic differences in the inventory and phonological shape of language-particular functional material, and (ii) transparency, whereby systematic variation in form arises from systematic variation in the meaning of basic lexical items.