alt Hacker NewsThe heritability statistic that occurs in the literature is the ratio of genetic variance to phenotypic variance.
Two corrollaries:
* When discussing heritability results from the literature, we are discussing that statistic, not your intuitive understanding of what the word should mean.
* In the scientific literature, your conception of heritability doesn't operate. In the scientific sense, the number of hands you have has low heritability, despite being genetically determined.
I think you're going to find "let's check Wiktionary" is not the decisive move in these kinds of discussions that it is elsewhere.
Another great example of the unintuitiveness of heritability is the fact that earrings are highly heritable. Earrings are highly correlated to a specific genetics (being female), so they're very "heritable", even though that correlation is an arbitrary cultural fashion.