fathom

1. (chiefly nautical, historical, US) A 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.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."; "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"UShistorical

2. (chiefly nautical, historical, US) A 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.Synonyms: stade, toise, brace, braza, estadio, orguiaUShistorical

3. (nautical, US) A measure of distance to shore: the nearest point to shore at which the water depth is the value quoted.Examples: "After we'd rowed for an hour, we found ourselves stranded ten fathoms from shore."; "At fifty fathoms, the waters of the Southern Ocean are dark blue."US

4. (figuratively)figurativelyin-plural

5. (figuratively)Examples: "Another of his fathome they haue not / To leade their buſineſſe, […]"archaicfigurativelyobsolete

6. (obsolete)obsolete