is 信号 traffic lights or like... a phone signal??

ok so i keep seeing 信号 and my brain keeps translating it to like... trusting a number? because of the kanji 信 and 号. but then my app says it means traffic light??? and then i mixed it up with 行列 because i thought that meant traffic too... wait is 信号 actually just a phone signal or a street light? how are these even the same word idk