(1) Non-substantive and generally insoluble materials, such as China clay, gypsum, etc., added to fabrics together with starches or gums during finishing to add weight or to modify their appearance and handle.
Note 1: This term is usually applied only to cellulosic textiles (see also loading). Finishes in which starches or gums are used without the addition of insoluble materials are sometimes referred to as ‘fillings’ but are more correctly described as ‘assisted finishes’.
Note 2: The equivalent term in North America is ‘filler’.
(2) A synonym, used in North America, for weft yams (see weft)
See wadding thread
Textile Resource (http://www.textile.org.uk)