American Heritage Dictionary - Cite This Source buff·er2 (bfr) Pronunciation Key
n.
Something that lessens or absorbs the shock of an impact.
One that protects by intercepting or moderating adverse pressures or influences: “A sense of humor... may have served as a buffer against the... shocks of disappointment” (James Russell Lowell).
Something that separates potentially antagonistic entities, as an area between two rival powers that serves to lessen the danger of conflict.
Chemistry. A substance that minimizes change in the acidity of a solution when an acid or base is added to the solution.
Computer Science. A device or area used to store data temporarily.

tr.v. buff·ered, buff·er·ing, buff·ers
To act as a buffer for or between.
Chemistry. To treat (a solution) with a buffer.
Computer Science. To hold or collect (data) in a buffer.