the.com/fathom
a unit of depth that became a verb for the depths you can't measure.
exact lengthsix feet, the span of outstretched arms
old rootsfrom a word meaning embrace or outstretched arms
sailor mathdepth once measured by armspans of rope
figurative depthto fathom means to understand the unfathomable
twenty thousandVerne's leagues measured distance, not depth