Inka

Certificates awarded by a Zen master to a student that signified the holder had achieved some degree of enlightenment in Zen.
Found on http://www.samurai-archives.com/vocab.html

Inka

Inka is a cultivated variety of potato.
Found on http://www.probertencyclopaedia.com/browse/QI.HTM

inka

seal of approval; acknowledgement by a Master that a pupil has completed his/her training
Found on http://www.encyclo.co.uk/local/20455
No exact match found