n. [ Prop a striker. See Buffet a blow. ] 1. (Mech.) (a) An elastic apparatus or fender, for deadening the jar caused by the collision of bodies; as, a buffer at the end of a railroad car. (b) A pad or cushion forming the end of a fender, which receives the blow; -- sometimes called buffing apparatus. [ 1913 Webster ]

2. One who polishes with a buff. [ 1913 Webster ]

3. A wheel for buffing; a buff. [ 1913 Webster ]

4. A good-humored, slow-witted fellow; -- usually said of an elderly man. [ Colloq. ] Dickens. [ 1913 Webster ]

5. (Chem.) a substance or mixture of substances which can absorb or neutralize a certain quantity of acid or base and thus keep the degree of acidity or alkalinity of a solution (as measured by pH) relatively stable. Sometimes the term is used in a medical context to mean antacid. [ PJC ]

6. (Computers) a data storage device or portion of memory used to temporarily store input or output data until the receiving device is ready to process it. [ PJC ]

7. any object or person that shields another object or person from harm, shock, or annoyance; as, the President's staff is his buffer from constant interruptions of his work. [ PJC ]

v. t. (Chem.) to add a buffer{ 5 } to (a solution), so as to reduce unwanted fluctuation of acidity. [ PJC ]

a. (Chem.) containing a buffer{ 5 }; -- of solutions, usually aqueous solutions. [ PJC ]

n. The head of a buffer, which recieves the concussion, in railroad carriages. [ 1913 Webster ]

n. [ trademark. ] a brand of aspirin tablets coated with a substance capable of neutralizing acid (a “buffer”); -- sometimes applied generically to any buffered aspirin preparation.
Syn. -- buffered aspirin. [ WordNet 1.5 ]