fathom

Pronunciation

• IPA: /ˈfað(ə)m/ (UK); /ˈfæðəm/ (US)^[1]

Etymology

It is inherited from Middle English fadme, fathme,^[2][3][4] inherited from Old English fæþm (“outstretched arms; embrace; grasp”),^[3][2][5][6] from Proto-Germanic *faþmaz,^[5][6] from the PIE root *pete- “to spread”.^[6][3] It is cognate with Dutch vadem, German Faden “thread, fathom” and Old Norse faðmr “embrace”,^[5][6][4] and akin to Latin patēre “to be open”.^[2]

Earliest recorded meaning

In Old English, the embracing arms, or the bosom; and figuratively, grasp or power (a1000).^[7][6][5] The measure of length covered by the outstretched arms is recorded from a800.^[7]

Semantic evolution

A fathom was the span of a man's outstretched arms, reckoned at about six feet,^[7][6][1] and became the standard unit for measuring the depth of water.^[3][2][1] The Old English verb meant “to embrace, encircle with the arms”.^[6][7][5] From the depth measure came the verb “to take soundings” (1607),^[7][2][5] and from that, figuratively, “to get to the bottom of, understand thoroughly” (1625).^[7][5][6]

Timeline

• a800 – the length of the outstretched arms, as a measure.^[7]
• a1000 – the embracing arms; grasp, power.^[7]
• c1300 – verb, to encircle with the arms.^[7][5]
• 1604 – breadth of comprehension (obsolete).^[7]
• 1607 – verb, to take soundings.^[7][2][5]
• 1625 – verb, to understand thoroughly.^[7][5]
• 1634 – verb, to measure the depth of water.^[7]

Modern meaning

Noun

1. A unit of length equal to six feet (about 1.83 metres), used chiefly to measure the depth of water.

Verb

1. To understand something fully; to get to the bottom of.
2. To measure the depth of water; to sound.

Word family

• fathomable
• fathometer
• fathomless
• unfathomable

Related words

• patent

Usage notes

At sea a fathom measures only depth, so a boat “100 fathoms offshore” is at the nearest point where the water is 600 feet deep, not 600 feet from the shore.^[1] The verb is most often used in the negative, as in couldn't fathom.^[2][4]

References

1. ^ a b c d Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Merriam-Webster's Collegiate Dictionary (2003), 11th ed., Springfield, Mass.: Merriam-Webster
3. ^ a b c d The American Heritage Dictionary of the English Language (1992), 3rd ed., Boston: Houghton Mifflin
4. ^ a b c Random House Webster's Unabridged Dictionary (1999), 2nd ed., New York: Random House
5. ^ a b c d e f g h i j Barnhart, Robert K., ed. (1995), The Barnhart Concise Dictionary of Etymology, New York: HarperCollins
6. ^ a b c d e f g h Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
7. ^ a b c d e f g h i j k l m Simpson, J. A.; Weiner, E. S. C., eds. (1989), The Oxford English Dictionary, 2nd ed., Oxford: Clarendon Press