What does "fathom" mean?

Fathom: The measure or extant of one's capacity; depth, as of intellect; profundity; reach; penetration. [R.] Another of his fathom they have none To lead their business. Shak.

Additional senses

  1. 2.To encompass with the arms extended or encircling; to measure by throwing the arms about; to span. [Obs.] Purchas.
  2. 3.The measure by a sounding line; especially, to sound the depth of; to penetrate, measure, and comprehend; to get to the bottom of. Dryden. The page of life that was spread out before me seemed dull and commonplace, only because I had not fathomed its deeper import. Hawthotne.

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