Flexibility is one of the most sought-after properties in modern manufactur
ing systems. Despite this interest, flexibility remains poorly understood i
n theory and poorly utilized in practice. One reason for this is the lack o
f general agreement on how to define flexibility: over 70 terms (types and
measures) can be found in the literature. This paper concerns developing a
framework and classification scheme for use in defining and classifying the
various terms regarding flexibility found in manufacturing. The framework
consists of six attributes: level of manufacturing requirements specificati
on, manufacturing system specification, manufacturing environment specifica
tion, flexibility dimension, flexibility measurement approach, and time fra
me. A six-field hybrid classification scheme is developed based on this fra
mework. The framework serves as a guide for developing new flexibility term
s, whereas the classification scheme provides a mechanism for summarizing t
he important aspects of and assumptions behind a given term. The approach i
s demonstrated by using the classification scheme to classify over 50 exist
ing flexibility terms. The results indicate that the classification scheme
is an effective tool to aid in understanding different flexibility terms an
d how they compare to one another. At the same time, the difficulty of the
classification exercise indicates the need for a suitable framework when de
fining such terms.