This study aims to identify the semantic range and differences in terms for the main structural members of vernacular timber houses in Japan and Britain, focusing on the understructure. Analysis of terms in glossaries and publications identified key characteristics of arrangement and terminology. The terminology of posts (hashira) and plates (keta) varies depending on the nave (joya)-aisle (geya) arrangement. Due to the truss arrangement, British beams are basically set crosswise, whereas Japanese beams are set crosswise and lengthwise and have various names. In Britain, curved timbers are framed symmetrically in a truss, whereas in Japan they are used supplementarily.
