Material utilized as fill between wall space of better structural integrity, particularly in masonry.
The interior part of scores of masonry, as the part between your up-stream and down-stream faces of a masonry dam. Frequently labeled as the backing.
The impervious straight wall surface of masonry, concrete, as well as clay puddle that is placed inside an earth embankment which types a dam or a reservoir bank, for the purpose of stopping leakage through embankment. Commonly called core-wall if of masonry or concrete, and puddle-wall if of clay.