The two words are used to mean the same thing. See:
http://www.ngdc.noaa.gov/seg/geomag/declination.shtml

Declination is also be used to indicate the position of celestial bodies. When so used, it is used in the same way that latititude is used on the surface of the Earth. If the sun has a declination of 18 degrees south, then it is going to be right above 18 degrees south latitude.

I got a Doug Ritter PSK from my local Dick's Sporting Goods. When I got it home the first thing I did was to unpack it, familarize myself with the contents and check everything out. To my dismay the compass wasn't even close to north, more like 25 degrees off to the east. I double checked it against my Victorinox "go that away" compass/ruler/thermometer. Then double checked it against my LC-1 Cammenga military compass......it was just plain off. So back to Dick's I went. They cheerfully exchanged it, although I was sure to check the compass out first. They can work in the pouch, but not overly reliable. Have to make darn sure the button compass is level in relation to orientation to the ground vs. in the pouch otherwise the card will hang up giving a false reading. Overall well pleased with the PSK, god knows I cannot disipline myself to make one that small and functioal. My hats off to Doug on that one. Saved me the hassle/heartbreak. Now I can just concentrate on making a cargo pocket sized small kit and trust Doug's PSK for true pocket carry.

-Bill Liptak