British For “Polyester”

Why is this Our Legacy trench/Macintosh looking thing called a "bomber"? Am I missing something on what constitutes a bomber? To me, a bomber jacket is cropped and inspired by classic MA-1 styles worn by pilots who flew, no shit, bomber planes. As you can see, this coat is neither. What this coat is, however, is a v streamlined waterproof style constructed out of "high shine Polyeurethene," which I'm pretty sure is just how a pretentious British person says "polyester". Ain't nothing 'Murican happening here.