long. is the written short form of longitude: how far east or west a place is on the Earth, measured in degrees from an imaginary line through Greenwich in London. You meet it on maps, in GPS, and in geography homework, often next to lat. (latitude, how far north or south). A typical line looks like “lat. 25° N, long. 121° E” for Taipei. You almost never say “long” out loud to mean this; when you speak, you say the full word longitude. The little dot is there to show it is an abbreviation, not the ordinary adjective long (as in a long road), and not the verb long (I long for home). On a globe, lines of longitude run from pole to pole; the number tells you the east–west slot.