It appears to be a grey area and does not appear to have an explicit definition aside from religion in many jurisdictions. Even those jurisdictions that discuss a broader definition, seem to shy away from actually doing so. Note that this is only a cursory search and experts in various jurisdictions may come up with more detailed results.
This case seems to mean that it is a formal declaration of a recognized religion.
Creed Legal Definition
The word creed imports a formal declaration of religious belief. The
word has no reference to benevolent, philanthropic or fraternal
organizations, secret or otherwise, even though of a moral character.
[Hammer v. State, 173 Ind. 199 (Ind. 1909)].
Says that it appears to be based on religion, but shows that (in Tennessee at least) there is no specific case law on the matter.
Since the law has not yet established what “creed” means, as far as
prohibiting employment discrimination on that basis, employers have
little guidance in this area. If an employee presents a non-religious
but sincerely held belief, will that be enough to be considered a
“creed” by the courts? With only a gut feeling to go by, we think it
likely that Tennessee courts will lean toward the view that “creed”
and “religion” are synonymous terms; thus, veganism, for example,
since it does not constitute a religious belief, would not be a
protected group under the THRA. However, to play it safe, employers
should refrain from passing judgment or making derogatory comments
regarding an employee’s expressed beliefs.
The hard part will come when an employer is faced with a situation
that may appear he is terminating an employee due to his creed.
Sooner or later, the courts will be ruling in such cases. While we
tend to think that Tennessee will decide that creed equals religion
(for THRA purposes), the last time we checked, the courts were not
giving us a vote on the question. So, employers, proceed with care!
Ontario Human Rights Commission
Various other cases have left open the possibility that non-religious
belief may constitute a creed under the Code (as discussed below).
Overall, the courts appear to be reluctant to offer any final,
authoritative, definitive or closed definition of creed, preferring a
more organic, analogical (“if it looks like a duck, walks like a duck
and quacks like a duck, it must be a duck”) case-by-case
assessment. This has yielded a variety of results. Courts and
tribunals have recognized a wide variety of subjectively defined
religious and spiritual beliefs within the meaning of creed under the
Code and religion under the Charter, including:
Aboriginal spiritual practices,
Practitioners of Falun Gong
Members of the Worldwide Church of God
Rocky Mountain Mystery School.
There is nothing in the case law that would prohibit redefining
“creed” more broadly and include secular ethical and moral beliefs.
Therefore, the question of what should constitute a creed in terms of
the right to be free from discrimination under the Ontario Code – in
particular with respect to secular, moral or ethical beliefs – remains
an open one. In fact, this is a central question being considered in
the current creed policy update. At the same time, the courts have
offered some guidelines around the outer limits of what they will
recognize as meriting protection under the Code ground of creed (as