The document emphasizes the importance of clearly defining terms in educational settings to avoid confusion. It highlights that definitions should differentiate clearly what a term means and not mean, especially when terms may have different meanings in common usage. Additionally, it stresses the need for consistency in using defined terms throughout the course.

1. Principle 2
Define terms
Glenn Martin
March 2017

2.  Define your terms, then use those terms
consistently throughout the course.

3.  Question:
 Does the material involve terms that:
• are likely to be unfamiliar to students? or
• will be used with a different meaning to the meaning
students are familiar with?
Example: in a Physics course, “force” has a particular
meaning – mass times acceleration.
[In general conversation, people use words in ways that
are consistent with the definitions found in common
dictionaries.]

4. If a term needs to be defined, keep this in mind:
 A good definition differentiates between what is
“the thing” and what is not “the thing”.

5.  A good definition makes it as clear as possible
what is the thing that is being defined, and what
is not “the thing”.
 The importance of a good definition is that it
enables us to differentiate “the thing” from other
things with which it could be confused.
 Example: How would you define “power”?

6. Suppose we have a
definition of “power”.
If it is a good definition,
it will clarify the distinctions
between power and other
concepts with which it
might be confused.

7. Is one concept
a subset of the
other? (A or B)
A B
C
Do the concepts overlap? (C)
D
What are the connections
between the concepts? (D)

8. If a term is used in a way that is different from what
would be found in a common dictionary, there must
be justification for the specialised use. This
includes:
 authority for the new meaning (e.g. academic
source)
 need for the new meaning (e.g. in order to
explain phenomena)
 proposed application of the new meaning.

9.  Having defined a term in a particular way, it must
be used with that meaning consistently
throughout the course.
 Care is needed not to, at any point, confuse the
ordinary sense in which a term is used with the
meaning it has been assigned in the course.