Lawyers will always tell you that a trust is not an entity. Its a legal relationship. But many laws say otherwise. Other laws do a similar thing eg Superannuation Law. eg Income Tax Assessment Act 1997 definition (s995.1) refers to the definition of entity (s960-100) and this includes a trust as an entity for the purposes of tax law. Its well described in the notes to s960-100 as a simple way to "refer to all types of taxpayers in all their different capacities so that in practice they are treated as having a separate identity in the same way a legal person does". A person can also have more than one capacity allowing them to each be a different entity. A good example of this occurs with trusts. A person can be a sole trustee, one of many trustees of another trust and the person. ie Three entities perhaps.
A trust is not a legal person, only a human or a company is a legal person. But a trust is an entity for tax purposes, same as a partnership.