n. A part of a seat (of a chair) designed to support the arm.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a support for the arm
Word Usage
"The mobile occasional table, which can also be used as an armrest, is quite deliberately an asymmetrical, unique piece, whilst the lumbar cushions, filled with pure down, also contribute to the general adaptability and freedom of use."