In Translation Studies the definitions of the concepts native speaker and mother tongue have been uncritically adopted from linguistics and are regarded as defined and clarified as far as their meaning is concerned, despite the fact that neither linguistics nor translation theory can offer an objective and water-tight definition of the terms. A similar desire for univocal terms can also be detected in the claims for the need of one, universally accepted term for the same phenomenon where various competing terms already exist and are in use. Although some linguists have already expressed their doubts in the justification of some of the fundamental linguistic concepts, as Rajogopalan has observed, a lot of them are still happy working with such discreet entities thus making linguistics perhaps the most '19th century' of the academic disciplines taught in universities today. Unfortunately, this could also be stated for some currents in Translation Studies, despite the fact that translation research can and should provide the most suitable field where such axiomatic truths are challenged. The article questions this desire for the univocal and argues that it is high time we all learn to live with more fuzzy definitions.