This paper studies English and Lithuanian two-word terms of building and civil engineering with respect to their grammatical and semantic structures. By means of a comparative analysis common and diverse structures of the terms under discussion have been considered, and some main two-word parallel term structures are distinguished in these languages. Structural differences are characterized by the grammatical peculiarities of the two languages. Semantic equivalence or non-equivalence of some components of such terms is discussed, and the adequacy of the meaning of the terms compared is explained. The comparative study of such terms should add to quick recognizing of certain structures and to facilitating comprehension and use of the terms. The adequacy of the English and Lithuanian terms means the identity of their meaning, and namely, this is what matters in special-subject communication.