A Rather rugged, perhaps even Gaelic sounding word? Reminds me of rolling around in the heather. Not that I often get the chance to roll around with someone called Heather. And of course the word has nothing to do with Scotland or heathen, heather filled landscapes.
Great word though.
n. pl. pe·num·brae (-br) or pe·num·bras
1. A partial shadow, as in an eclipse, between regions of complete shadow and complete illumination. See Synonyms at shade.
2. The grayish outer part of a sunspot.
3. An area in which something exists to a lesser or uncertain degree:
4. An outlying surrounding region; a periphery:
aNOtHEr dIp INtO ThE mAGpIE mEMOrY pOOoL.