If someone is your carer are they your step parent?

A step parent is someone that is married to your mom and/or dad, they will then be a type of carer for a younger child as well. But you could have a carer who is not related to you by blood or marriage as well, a legal gardian who was appointed to care for a child, such as a god parent or a family friend or a foster parent, they would not be called a 'step parent' then.