fathom (v.)

1.to look at critically or searchingly, or in minute detail"he scrutinized his likeness in the mirror"

2.measure the depth of (a body of water) with a sounding line

3.come to understand

fathom (n.)

1.(mining) a unit of volume (equal to 6 cubic feet) used in measuring bodies of ore

2.a linear unit of measurement (equal to 6 feet) for water depth