"prerequisite understanding" is a correct and usable term in written English.
It is typically used to emphasize the need for someone to have a basic understanding of a concept or topics in order to move forward. For example, "Before we can discuss this advanced topic, we need to have a prerequisite understanding of the basics."
Understanding the relevant notions is thus a prerequisite for understanding key issues in contemporary analytic philosophy.
Understanding the interaction between two or more "hits" is a prerequisite for understanding mechanisms of permanent lung injury in preterm infants and for individualization of therapeutic interventions in order to promote recovery from the stressors.
Understanding the phylogenetic relationships within the Neodermata is an essential prerequisite for understanding the evolutionary origins of endo- and ectoparasitism as well as of the complex life cycles of flatworms.
Understanding the molecular mechanisms underlying plant defenses and fungal pathogenicity is a prerequisite for understanding the host-pathogen interaction and can contribute to the development of new strategies of crop protection against pathogen.
Understanding the molecular regulation of the individual cell types in complex tissues is, therefore, a prerequisite for understanding disease states.
Respect is a prerequisite for understanding.
And comprehending this fury is a prerequisite to understanding the importance of war crimes tribunals.
There is mathematics cooked into the tools, but knowing what sine and cosine mean is not a prerequisite to understanding how they work.
Frusciante describes it as a concept album (about two characters that exist in the mind of one person over the course of a lifetime) but esoteric knowledge is not a prerequisite to understanding it.
The real impact of this long tradition is, however, not in the field of business or diplomacy or mathematics or exploration; it is because mastery of a foreign language is a prerequisite for understanding how to use your own.
