Spoke and nipple compatibility
With wire (and spokes) a larger number for gauge is a smaller diameter.

This is why the metric conversion seems the other way around.

14 / 2mm is the larger diameter here, and yes, it's at the ends, or rather, the hub end.

Straight spokes are straight, single butted are thicker at the hub end, double are thicker at both ends, and triple butted are thickest at the hub end, narrow in the middle and slightly thicker at the nipple end. Says Sheldon.