Today's fantastic little word is:
A badge or characteristic device - in this sense, it is synonymous with and etymologically identical to the Latin-derived insignia. However, episemon also means one of three obsolete Greek letters (vau, qoppa and sampi) used solely in the Greek alphabetical numeral system.
From Greek, a badge, from epi, on, and sema, a sign.
Yesterday, a colleague wandered over to say hello and noted the desktop wallpaper on my computer that sat there in lieu of the pretty clouds-and-grass that comes default on Windows XP computers. Asking me what it was, I told him it was my family's episemon - represented by a bull between two flags, circled in a strap and buckle with the words HOLD FAST over the top - the crest of the MacLeods of Harris, Uist and Skye.
This prompted him to ask me, quite innocently: what's long, hard, and filled with episemon?
I'll leave it up to you nice folks to finish that joke. :D