fathom

plural fathoms

1. UShistoricalnauticalA man's armspan, generally reckoned to be six feet (about 1.8 metres). Later used to measure the depth of water, but now generally replaced by the metre outside American usage.

   Full fadom fiue thy Father lies, Of his bones are Corrall made: Those are pearles that were his eies, Nothing of him that doth fade, But doth suffer a Sea-change Into someting rich, & strange

   1610–1611 (date written), William Shakespeare, “The Tempest”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act I, scene i], page 5, column 1

   2 more examples

   [T]he ſhipmen deemed that they drew neere to ſome countrey: And ſounded, and found it twentie fathoms: and when they had gone a little further, they ſounded againe, and found it fifteene fathoms.

   1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], →OCLC, Acts 27:27–28, column 2

   And then they told me that a good many years ago, when the speakers were boys, some Wokan men who were out fishing met these lost people in the sea, and spoke to them; and the chief gave the Wokan men a hundred fathoms of cloth to bring to the men of Wanumbai, to show that they were alive and would soon come back to them[.]

   1869, Alfred Russel Wallace, The Malay Archipelago, volume II, London: Macmillan and Co., page 262

   1. UShistoricalnauticalAn internationally standardized version of this unit, the international fathom (= 1.8288 metres = 6 feet).

      Synonyms: stade, toise, brace, braza, estadio, orguia

2. USnauticalA measure of distance to shore: the nearest point to shore at which the water depth is the value quoted.

   After we'd rowed for an hour, we found ourselves stranded ten fathoms from shore.

   1 more example

   At fifty fathoms, the waters of the Southern Ocean are dark blue.

   1983, Richard Ellis, “The Predators”, in The Book of Sharks, 1st paperback edition, New York, N.Y.: Alfred A[braham] Knopf, published 1989, →ISBN, page 7

3. figurativelyin pluralAn unspecified depth.
4. archaicfigurativelyobsoleteDepth of insight; mental reach or scope.

   Another of his fathome they haue not / To leade their buſineſſe, […]

   c. 1603–1604 (date written), William Shakespeare, The Tragœdy of Othello, the Moore of Venice. […] (First Quarto), London: […] N[icholas] O[kes] for Thomas Walkley, […], published 1622, →OCLC, [Act I, scene i]

5. obsoleteThe act of stretching out one's arms away from the sides of the torso so that they make a straight line perpendicular to the body.
6. obsoleteSomeone or something that is embraced.

   Thy Bride, thy choice, thy vvife, / She that is novv thy fadom, […] Kneele at thy feete, obay in euerie thing, / So euerie Father is a priuate King.

   1601 (first performance), Thomas Dekker, Satiro-mastix. Or The Untrussing of the Humorous Poet. […], London: […] [Edward Allde] for Edward White, […], published 1602, →OCLC, signature E, verso

7. figurativelyobsoleteControl, grasp.

   So; novv knovv I vvhere I am, me thinkes already / I graſpe beſt part of the Autumnian bleſſing / In my contentious fadome, […]

   1604 (first performance), [Thomas Middleton], “Inductio”, in Michaelmas Terme. […], London: […] [Thomas Purfoot and Edward Allde] for A[rthur] I[ohnson] […], published 1607, →OCLC, signature A2, recto

   1 more example

   Yes: / you have blovvne his ſvvolne pride to that vaſtnes, / as he beleeves the earth is in his fadom, / this makes him qute forget his humble Being: […]

   1622 May 24 (licensing date; Gregorian calendar), John Fletcher, Philip Massinger, “The Prophetesse”, in Comedies and Tragedies […], London: […] Humphrey Robinson, […], and for Humphrey Moseley […], published 1647, →OCLC, Act II, scene i, page 29

present singular third person fathoms · participle present fathoming · participle past fathomed · past fathomed

1. alsofigurativelytransitiveTo measure the depth of (water); to take a sounding of; to sound.

   It is very steep, and on its summit is a lake of dark water, so deep that it cannot be fathomed.

   1850, Thomas Keightley, The Fairy Mythology, London: H.G. Bohn, page 457

2. archaicobsoletetransitiveTo encircle (someone or something) with outstretched arms; specifically, to measure the circumference or (rare) length of something.
3. figurativelytransitiveOften followed by out: to deeply understand (someone or something); to get to the bottom of.

   I can’t for the life of me fathom what this means.

   1 more example

   Otamendi’s selection ahead of Vincent Kompany was difficult to fathom and, apart from Fernandinho, City’s line-up was otherwise filled with attacking players.

   2018 April 10, Daniel Taylor, “Liverpool go through after Mohamed Salah stops Manchester City fightback”, in The Guardian (London)

   Synonyms: figure out, puzzle out, work out

4. obsoletetransitiveTo embrace (someone or something).
5. intransitiveTo measure a depth; to sound.
6. figurativelyintransitiveTo conduct an examination or inquiry; to investigate.