What is "back filling"

Back \Back\, a.

1. Being at the back or in the rear; distant; remote; as, the back door; back settlements.

2. Being in arrear; overdue; as, back rent.

3. Moving or operating backward; as, back action.

   Back blocks, Australian pastoral country which is remote from the seacoast or from a river. [Webster 1913 Suppl.]

   Back charges, charges brought forward after an account has been made up.

   Back filling (Arch.), the mass of materials used in filling up the space between two walls, or between the inner and outer faces of a wall, or upon the haunches of an arch or vault.

   Back pressure. (Steam Engine) See under Pressure.

   Back rest, a guide attached to the slide rest of a lathe, and placed in contact with the work, to steady it in turning.

   Back slang, a kind of slang in which every word is written or pronounced backwards; as, nam for man.

   Back stairs, stairs in the back part of a house; private stairs. Also used adjectively. See Back stairs, Backstairs, and Backstair, in the Vocabulary.

   Back step (Mil.), the retrograde movement of a man or body of men, without changing front.

   Back stream, a current running against the main current of a stream; an eddy.

   To take the back track, to retrace one's steps; to retreat.

Filling \Fill"ing\, n.

1. That which is used to fill a cavity or any empty space, or to supply a deficiency; as, filling for a cavity in a tooth, a depression in a roadbed, the space between exterior and interior walls of masonry, the pores of open-grained wood, the space between the outer and inner planks of a vessel, etc.

2. The woof in woven fabrics.

3. (Brewing) Prepared wort added to ale to cleanse it.

   Back filling. (Arch.) See under Back, a.