Simply put, a delta-wing is a triangular wing planform.

地说，三角翼就是三角型的翼面。

The observed deltas are highly two-dimensional in planform, adopting palmated structures which retain throughout their evolution a high degree of mirror symmetry.

实验观察到的三角洲，为一高度维蹼狀发展且镜面对称的构造。