Dear Faldage: I just got a surprise. The next word on spelling bee list is "patulous", which I first encountered in an obstetrical record of a woman who had had fourteen children, and as result had "a patulous cervix" - meaning that instead of admitting a catheter with moderate force, it would readily admit a couple fingers. The surprise came when the defintion told me to look up "fathom".
fathom
n.
5ME fadme < OE f+thm (akin to OFris fethm, OS pl. fathmbs), the two arms outstretched (to embrace, measure), akin to Ger faden, thread < IE base *pet3, to stretch out > L patere, to stretch out6 a length of 6 feet, used as a unit of measure for the depth of water or the length of a rope or cable
vt.
1 to measure the depth of; sound
2 to get to the bottom of; understand thoroughly
fath4om[a[ble
adj.