The article brings into focus variability of designation in bilingual terminology transfer. Onomasiological view of terminology equivalence presumes decontextualized coordination of concepts and linguistic labels and thus infers “one-to-one” inter-language terminology relation. This guiding principle is rarely applied in actual LSP translation process resulting in term forms variation. The gap between prescriptions and performance is traditionally accounted for as the arbitrary treatment of terminology by translators. Patterns of term variation in the reality of LSP translation depend on systemic, semantic and formal characteristics of terminology and, as a result, bear on terminology translation as a problematic concept.