yellow light of traffic lights, yellow signal, amber light, amber signal

a traffic light

a green traffic light, a green light (abbr. 青), green signal

red light of traffic lights, red signal

the act of crossing or entering an intersection ignoring a traffic signal (on foot or with a vehicle); jaywalking / one who runs a red light or stop sign

to cross or enter an intersection ignoring a traffic signal (on foot or with a vehicle); jaywalk / to pass a red light or stop sign without stopping

(maritime) signal flag

Synonym of モールス符号 (Mōrusu fugō, “Morse code”)

flag semaphore

(nautical) quarantine flag