Reduce

from dictionary.com
re · duce
v. tr.

To bring down, as in extent, amount, or degree; diminish.
To bring to a humbler, weaker, difficult, or forced state or condition; especially:

To gain control of; conquer: “a design to reduce them under absolute despotism” (Declaration of Independence).
To subject to destruction: Enemy bombers reduced the city to rubble.
To weaken bodily: was reduced almost to emaciation.
To sap the spirit or mental energy of.
To compel to desperate acts: The Depression reduced many to begging on street corners.
To lower in rank or grade.
To powder or pulverize.
To thin (paint) with a solvent.

To lower the price of: The store has drastically reduced winter coats.
To put in order or arrange systematically.
To separate into orderly components by analysis.

Chemistry.

To decrease the valence of (an atom) by adding electrons.
To remove oxygen from (a compound).
To add hydrogen to (a compound).
To change to a metallic state by removing nonmetallic constituents; smelt.

Mathematics.

To simplify the form of (an expression, such as a fraction) without changing the value.

v. intr.

To become diminished.
To lose weight, as by dieting.
Biology. To undergo meiosis.

--------------------------------------------------------------------------------
[Middle English reducen, to bring back, from Old French reducier, from Latin redcere : re-, re- + dcere, to lead; see deuk- in Indo-European Roots.]
--------------------------------------------------------------------------------
I've highlighted the definitions that seem to apply right now.