"Defining principles" refers to the core beliefs or ideas that shape the way someone or something acts or operates. These principles serve as a guide or framework to determine values, decisions, and behaviors. Full definition
You get a nursing pillow with cover, so this product defines principles of added value. (wetheparents.org)
To define principles in the personal context, we perceive them to be rules or beliefs governing morally correct behaviour and attitudes. (the-positive-parenting-centre.com)
We do this by clearly defining our principles, staying in our role as a parent, and sticking to our bottom lines. (empoweringparents.com)