Sentence:  The word "<WSD>pile</WSD>" is used specifically to mean the column of superposed electrodes, such as that of w:voltaic pile 
Meaning of the word marked with <WSD> tags:  A vertical series of alternate disks of two dissimilar metals (especially copper and zinc), laid up with disks of cloth or paper moistened with acid water between them, for producing a current of electricity; a voltaic pile, or galvanic pile.