Access to justice
The term "justice" in the phrase "access to justice" refers to the civil legal justice system (justice system). A person have access to justice when he has the ability to use the justice system to protect his legal rights.
To use the justice system, a person needs to know his legal rights and the legal process that must be followed to protect those rights. People can acquire this knowledge directly by learning, or rely on a knowledgeable expert (i.e., an attorney). Over 70% of people using the justice system do so without the help of an attorney due to either a) their inability to afford an attorney or b) the case doesn't warrant or allow the use of an attorney. This means they have to struggle to acquire sufficient knowledge to use it. An unknown number of additional people don't even take that step.
In many cases, effective use of the justice system requires people do do things prior to its use. For example, people want their heirs to inherit their property upon their passing, they will need to setup wills or trusts in advanced. That way, there won't be ambiguity later when the justice system is called upon to distribute their estates. This is why having access to justice encompasses not just the use of the justice system but also the preparatory steps that should be followed prior to its use.