the.com/breadth
How wide a thing reaches, measured sideways instead of skyward.
means The extent of something from side to side, or by extension its range and scope.
from A 1500s upgrade of the older 'brede,' fitted with the -th ending stolen from 'length' so the two could be measured as a matching pair.
Width's cousinWidth is the gap; breadth is the reach.
Hidden mathLength times breadth gives you area.
Figurative leapBreadth of mind means generous, wide-ranging thinking.