However, the term " collective noun " is often used to mean " mass noun " ( even in some dictionaries ), because users conflate two different kinds of verb number invariability : ( a ) that seen with mass nouns such as " water " or " furniture ", with which only singular verb forms are used because the constituent matter is " grammatically " nondiscrete ( although it may [ " water " ] or may not [ " furniture " ] be " etically " nondiscrete ); and ( b ) that seen with collective nouns, which is the result of the metonymical shift between the group and its ( both grammatically and etically ) discrete constituents.
