- Sewage is defined as waste matter and excrement carried away in drains.
Waste matter that you flush down your toilet that gets carried away in the sewer is an example of sewage.
Raw sewage flows from a pipe polluting a river.
sewage definition by Webster's New World
Origin: sew(er) plush -age
sewage definition by American Heritage Dictionary
Origin: Perhaps sew, sewer (from Middle English, short for Anglo-Norman sewere; see sewer1) + -age.