In the present paper the authoresses describe the consecutive phases - the planning phase, the collection of material, the selection of data, and the construction and arrangement of entries - in the compilation of an English-Polish glossary of lexicographical terms, which is part of a larger dictionary project. In doing so, they address some of the issues that made the compilation procedure methodologically difficult. On theoretical grounds, the main dilemma was whether lexicographical or terminological principles should be followed, inasmuch as they result in conflicting features, i.e. different coverage, organisation and description of data. The most pertinent practical problem that they faced was, on the one hand, the variability of terms in English lexicographical discourse and, on the other one, the incompatibility of English and Polish terminological frameworks. For the glossary to be used successfully in text reception, they thus needed to determine the complex semantic relationships between intralingual terms and, even more importantly, the various levels of equivalence between interlingual terms. The issues discussed here have been illustrated with relevant English-Polish contrastive material.