Membership in a Rotary club is by invitation and was based on the founders' paradigm of choosing one representative or each business, profession and institution in the community. What is called the "classification principle" is used to ensure that the members of a club comprise a cross section of their community's business and professional life.
A Rotarian's classification describes either the principal business or professional service of the organization that he or she works for or the individual Rotarian's own activity within the organization. The classification is determined by activities or services to society rather than by the position held by the particular individual. In other words, if a person is president of a bank, he or she is not classified as "bank president" but under the classification "banking."..The classification principle fosters a fellowship for service based on diversity of interest, and seeks to prevent the predominance in the club of any one group.
When a person becomes an active member of a Rotary club, it is said that
a the member
has been "loaned" a classification. He or she may propose one additional
active member
in that classification. On completing five, ten or fifteen years of service,
depending on
the individual's age, he or she becomes a "senior active" member and their
classification
is released to enable another person to join the club.