The popular slang 1738 is pretty much associated with Fetty Wap, a famous rapper. He cryptically used it in his popular song, “Trap Queen”
Its origins are very similar to the previous slang “1942.” It is a type of luxury cognac or distilled spirit produced by Remy Martin. It commemorates King Louis XV. 1738 is stated to be the best liquor within the urban community.
Casually, it refers to any strong yet delicious type of alcohol, preferably brandy. You would often hear it within rap circles that enjoy drinking. They may use it like:
“Ralph brought 1738 so drink up!”
“Julius wasted some good 1738 by giving it away.”