We will look at the issue of Tesoro Hebrew Etymologies, on the one hand, by rereading recent articles (published between 1994 and 2010) which all highlight their ideological dimension; on the other hand, by experimenting with a different approach, which consists of looking at these hebraic etymologies in the contrast they form with the Arab etymologies reported by the lexicograph for the same terms. I shall thus analyse the linguistic content of the commentary to the haematographic and Arabic etymologies made or reported by the lexicograph and will see that it follows from that approach that new conclusions are drawn on the different etymological methods applied in both cases by the lexicograph and on the respective statuses of Arabic and Hebrew in the Tesoro, as expressed not explicitly in the well-known leitmotiv, ‘the lengua arábiga es deduzida de la hebrea’, but implicitly in the linguistic treatment applied to each of those two languages.