FWF - Foundation for Wayward Frontiersman. A kind of cross between the Salvation Army and USO.
tm - tithemark, the currency of the frontier. After the Terran Empire occupies space it immediately introduces credits, which convert on a 1-to-1 basis since the Frontier is too far away to be worth trying to figure out an exchange rate. Post TE withdrawal the two terms are interchangeable.
UPF - United Planetary Federation. a Coalition of the four races that occupy the Frontier. It is not a unifying government, all four races maintain their own government, and all Star Systems maintain local governments and laws.
Void Space - This is what the Frontier calls Hyperspace. Out in the Frontier The Void is not a pleasant way to travel, there is always a constant feeling of dread when one travels in Void. Like something malevolent is watching, and waiting.