I like the Henrik Kniberg definition of culture, 'culture is the stuff people do without thinking about it'. E.g. you could codify most things as processes (which is basically the entire point of things like value stream maps), but a company culture is infuses the kind of things you don't need to make explicit, because they become self-evident.

Think Netflix travel policy ("be responsible") vs more traditional companies with rules and travel agents for implicit vs explicit, or cultural vs process driven.