n.

1. （鐵路的）臂板信號
2. 信號
3. 【軍】旗語

vt.

1. 用信號（或旗語）發出信息

vi.

1. 發信號；打旗語

n.

1. a system of sending messages by holding the arms or two flags or poles in certain positions according to an alphabetic code.
2. an apparatus for signalling in this way, consisting of an upright with movable parts.

v.