灯号

燈號
dēnghào
  1. flashing light
  2. indicator light

CEDICT

以灯光明灭作为信号。用来代替言语，互通信息，多用于交通上。

重編國語辭典

Entry Composition

1 灯 dēng
  1. lamp
  2. light
  3. lantern

classifier: 盞
2 号 hào
  1. ordinal number
  2. day of a month
  3. mark
  4. sign
  5. business establishment
  6. size
  7. ship suffix
  8. horn (wind instrument)
  9. bugle call
  10. assumed name
  11. to take a pulse
  12. classifier used to indicate number of people