bifacial
/baɪˈfeɪʃəl/adjective
1- having two faces, in particular有两个面的, 尤指：
1.1
- Botany (of a leaf) having upper and lower surfaces that are structurally different【植】（叶子） 异面的。
1.2
- Archaeology (of a flint or other artefact) worked on both faces【考古】（燧石或其他人工制品）经两面加工的。