[Footnote 5: In this and other examples taken from exotic languages I am
forced by practical considerations to simplify the actual phonetic
forms. This should not matter perceptibly, as we are concerned with form
as such, not with phonetic content.]

It is high time that we decided just what is meant by a word. Our first
impulse, no doubt, would have been to define the word as the symbolic,
linguistic counterpart of a single concept. We now know that such a
definition is impossible. In truth it is impossible to define the word
from a functional standpoint at all, for the word may be anything from
the expression of a single concept--concrete or abstract or purely
relational (as in _of_ or _by_ or _and_)--to the expression of a
complete thought (as in Latin _dico_ "I say" or, with greater
elaborateness of form, in a Nootka verb form denoting "I have been
accustomed to eat twenty round objects [e.g., apples] while engaged in
[doing so and so]"). In the latter case the word becomes identical with
the sentence. The word is merely a form, a definitely molded entity that
takes in as much or as little of the conceptual material of the whole
thought as the genius of the language cares to allow. Thus it is that
while the single radical elements and grammatical elements, the carriers
of isolated concepts, are comparable as we pass from language to
language, the finished words are not. Radical (or grammatical) element
and sentence--these are the primary _functional_ units of speech, the
former as an abstracted minimum, the latter as the esthetically
satisfying embodiment of a unified thought. The actual _formal_ units of
speech, the words, may on occasion identify themselves with either of
the two functional units; more often they mediate between the two
extremes, embodying one or more radical notions and also one or more
subsidiary ones. We may put the whole matter in a nutshell by saying