conception
This word operates on a spectrum between biological reality and mental architecture. When used biologically, it marks a definitive point of origin, carrying a clinical or reproductive weight. It is the precise moment something begins to exist physically.
In a cognitive sense, it describes the mental scaffolding used to understand a concept. While a definition is a set of rules, a conception is a personal or cultural mental image. It often implies a subjective interpretation, suggesting that two people can have entirely different conceptions of the same word, such as justice or love.
Countable when referring to a specific mental theory or a single biological event. Uncountable when referring to the general process of forming ideas or the state of becoming pregnant.