I. ˈfathəm noun
( -s )
Etymology: Middle English fadme, from Old English fæthm embracing or outstretched arms, fathom (unit of length); akin to Old High German fadum thread, Old Norse fathmr embracing arms, fathom (unit of length), Latin patēre to be open, pandere to spread, unfold, Greek petannynai to spread out
1.
a. obsolete : a full stretch of the arms in a straight line ; also : grasp , reach
b. : intellectual grasp, penetration, or profundity : comprehension
the themes display a newer fathom than the technical modernism of the composer's earlier works — Newsweek
2.
a. : a unit of length equal to 6 feet based on the distance between fingertips of a man's outstretched arms and used especially for measuring the depth of water — sometimes used in the singular when qualified by a number
five fathom deep
b. archaic : any of several units of length varying around 5 and 5 1/2 feet
c. Britain : the quantity of wood in a pile of any length measuring 6 feet square in cross section
d. : a unit of area equal to 6 square feet used by miners for measuring areas in the plane of a vein
II. verb
( -ed/-ing/-s )
Etymology: Middle English fadmen, from Old English fæthmian; akin to Old Norse fathma to embrace; derivative from the root of English fathom (I)
transitive verb
1. archaic : to encircle (as for measuring) with outstretched arms
2.
a. : to measure by a sounding line
b. : to penetrate (as a mystery) and come to understand : comprehend where one had not understood previously : get to the bottom of
found the man's motives very difficult to fathom
trying to fathom the universe — C.S.Kilby
intransitive verb
: to take soundings ; also : probe , investigate