A great deal of Aboriginal religious knowledge is restricted. Particular songs, designs, objects, narratives and places are held by particular people and may be seen, heard or spoken of only by those with the right, which typically depends on gender, on stage of initiation, and on descent or standing in relation to the country concerned. This is not secrecy for its own sake. Holding knowledge carries responsibility for it, and disclosing it to people without standing is a serious wrong against the holders and, in many traditions, dangerous to everyone involved.
Men's business and women's business are separately held in most traditions, each with sites, ceremonies and knowledge closed to the other. Early ethnographers, almost all male, recorded men's material and often concluded that women had little religious life; work from the 1970s onward by researchers with access to women's ceremony showed that conclusion to be an artefact of who was allowed to watch. Older published sources should be read with that in mind, and a good deal of what they printed was published without permission and is now formally restricted by the communities concerned.
Related conventions govern the dead. Many communities avoid speaking the name of a person who has died, or displaying their image, for a period after death or permanently, and substitute names are used instead. This is why Australian broadcasters and publications carry warnings that content may include images or voices of people who have died. It is a live protocol, not a historical curiosity.
The practical consequence for an encyclopedia is a limit that should be stated rather than worked around. This entry describes structure, and describes the fact of restriction, using material communities have made public. It does not reproduce restricted content, and any account that claims to give the full contents of a ceremony has either been given specific permission or has committed a breach.