[jrockway]

I think yellow and amber are a good example of similar confusion in English. According to the NYS driver's manual, traffic lights are yellow and marker lights on vehicles are amber. They both look yellow to me. Doing some research around the Internets, I see people insisting that governments always call traffic lights amber, but that's not true. Either way, nobody knows what "amber" means except people manufacturing lights and people that just looked it up because they're reading a comment about it. But, again, if you ask someone "is the middle traffic light amber?" they'd probably say yes, just like Japanese people will be happy to mark the green light as ao.