The etymological study of Early Irish began in the Old Irish period (c. 700-900 A.D.), under the influence of Isidore of Seville's Etymologiae, and, because of its flexible hermeneutic potential, it enjoyed great popularity in the middle and early modern period. It is only with the rise of modern comparative linguistics, especially of Indo-European linguistics in the second half of the 19 th century, that the art of Irish etymology has attained scholarly riguour. Over the past 150 years, paradigm shifts in Indo-European studies (laryngeal theory, accent/ablaut classes of inflection, derivational morphology) and the development of modern technology (digitisation of texts, eDIL, ISOS) have repeatedly changed the methods and the course of Irish etymological studies. The impact of some of these external factors will be illustrated with examples. Keywords Etymology of Celtic languages; etymology of Old Irish; OIr. ubull; OIr. cauru (cáera) 'sheep'; OIr. *cóennae 'moss' The history of lexicography of the Irish language, especially of Old Irish, has been treated in a recent survey article (Griffith et al. 2018). As the focus in that survey was on dictionaries and word-lists of the language as it is attested in manuscripts and, in the case of Modern Irish, in speech, etymological research and etymological dictionaries of Irish and related languages only received cursory attention. However, Irish etymological lexicography from its very peculiar beginningspeculiar from our modern scientific point of viewand the impact that progress in the comparative method and in the wider field of Indo-European studies had on it over the past two centuries deserves separate and closer attention. Paradigm shifts in Indo-European studies and, more recently, the development of electronic research technology have repeatedly changed the methods and the course of Irish etymological studies. This article will trace how the state of research in Irish represents the state of art in the wider ambit of diachronic linguistics: where it lags behind and where it is up to date with other philologies. In addition, I will underline my points with new etymological proposals for several lexemes of Old Irish. As a starting point, it is useful to position etymological research in Old Irish in relation to etymological resources available for the other Celtic languages. The situation is, generally speaking, sad. Given the very fragmentary nature of their evidence and the difficulties besetting even the simplest attempts at assigning meanings to the lexemes, all dictionaries of the extinct Celtic languages of antiquity, namely Celtiberian, Gaulish and Lepontic, have a more or less strong etymological component. Xavier Delamarre's dictionary of Gaulish (Delamarre 2003) is built on a solid basis of up-to-date Indo-European linguistics, even though older suggestions are not consistently transferred into modern i.e. laryngealistic notation. Given the nature of the evidence, a large part of the dictionary is based on onomastic material. Some caution is required as D...
