Scour vs Undefined - What's the difference?

As a verb scour

is to clean, polish, or wash something by scrubbing it vigorously.

is the removal of sediment caused by swiftly moving water.

lacking a definition or value.

* scower (obsolete)

(en verb)

To clean, polish, or wash something by scrubbing it vigorously.

He scoured the burner pans to remove the burnt spills.

To remove by rubbing or cleansing; to sweep along or off.

He scoured the burnt food from the pan.

* Shakespeare

[I will] stain my favors in a bloody mask, / Which, washed away, shall scour my shame with it.

To search an area thoroughly.

They scoured the scene of the crime for clues.

(ambitransitive) To move swiftly over; to brush along.

* Alexander Pope

when swift Camilla scours the plain

* Dryden

So four fierce coursers, starting to the race, / Scour through the plain, and lengthen every pace.

(veterinary medicine) Of livestock, to suffer from diarrhea.

If a lamb is scouring , do not delay treatment.

(veterinary medicine) To purge.

to scour a horse

(obsolete) To cleanse.

* Francis Bacon

Warm water is softer than cold, for it scoureth better.

* scourer

(-)

The removal of sediment caused by swiftly moving water.

Bridge scour may scoop out scour holes and compromise the integrity of the bridge.

(wikipedia undefined) (-)

Lacking a definition or value.

(mathematics, computing) That does not have a meaning and is thus not assigned an interpretation.

The result of division by zero is undefined .

* defined