Comparison of methods of derivation from prefixes and suffixes in Basque, Catalan and Spanish: lexicographic conclusions The purpose of this paper is to set forth some of the results of research by working groups at the above universities over the last three years. This study is part of the project titled Configuración morfológica y estructura argumental: léxico y diccionario, subsidised by the Spanish Education Ministry and based on a three-viewpoint approach. Firstly, derivation processes based on prefixes and suffixes have been analysed in all three languages, with special emphasis on those cases in which the basis for derivation is a verb and those in which the derivative is a verb. Two substantial differences have been found: one is between prefixes and suffixes within Basque and the other is between Basque derivatives and those of romance origin. Secondly, a theoretical exposition of these two differences has been sought and found. Thirdly, we have attempted to consolidate the contribution of this theoretical exposition to the field of lexicography. This paper aims to bring together the theoretical exposition and our lexicographic conclusions. The differences which must be dealt with in any theoretical exposition are: a) the scarcity of prefixes in Basque as compared to the abundance of suffixes; and b) the fact that this imbalance is not shared by the romance languages. Our hypothesis is that a syntactic characteristic of Basque and the romance languages is extrapolated to their morphology, so that in Basque derivations the core of the structure is on the right, while in the romance languages it is on the left. To make this easier to understand, remember that prefixes in romance languages may act in two ways: as modifiers of a core, located on the left (refer/rehacer, desfer/deshacer, predir/predecir) or as the core, coming first with a complement on their right (eslomar-se/deslomarse, desfullar/deshojar). In the former case the prefix provides specificity for the core (the derivative predecir is a more specific version of the core decir, but to say before is, after all, still to say). In the latter case, the core is made up of the prefix itself, and the core is the basis of the derivation, so that prehistoria is not a more specific version of the basic complement historia but something different altogether. It can be seen in two ways that Basque has only the first form. First of all, it has the prefix des-, which has both possibilities, as in the case of the romance languages. In the derivative desegin it acts as a modifier of the basic core egin (the antonym of do), but when we seek an example of the prefix/core complement type (deshojar), desostatu, we find that it is not properly formed. Observe that the prefixes ber-/bir ''re' and ez- 'in-/des-'also act in the same way. As regards lexicographic conclusions, the first point which must be stressed in this paper is the difficulty found in forming words such as desostatu. Secondly, we must make it clear that the prefix-core/base-complement of the romance languages and English has a corresponding feature in Basque in base-complement/suffix-core. This is an important contribution to modern lexicography. Beyond formations of the des1 hoja2 r ??hosto2 gabe1 tu type we must bear in mind the option hostoak2 galdu/kendu1 but especially the forms pozoin-du (en-venenar), bigun-du (re-blancederse), lerro-ka-tu (a-linear), irin-ez-ta-tu (enharinar), lur-rera-tu (a-terrizar), which should be standardised as the common correspondents of the prefixes a-, des-, en-, es-, in- and re- so that more and better resources are made available.