You sound like you're thinking of things colloquially, to put things in a kind way. Heritability is not a colloquial term and in biology/genetics refers exclusively to genetic factors. In particular it's the percent of difference in some value that cannot be explained by non-genetic factors. So e.g. if my IQ is 130 and yours is 90 then we'd have a difference of 40 points. With an adult IQ heritability of 80% we'd expect that about 32 points of that would be unable to explained outside of genetic factors.

Heritability does change over time because environments change over time. For instance in an area where starvation, lead poisoning, and malnutrition was common, the heritability of intelligence (or height) would generally be quite low, because the aforementioned environmental factors would be able to explain a large chunk of the differences between populations. But in a society where everybody had practically identical relevant upbringings and opportunities, the heritability of intelligence would be 100%, because the only difference between people would be genetic.

One of the many ways to test for heritability is twin studies. You'll likely find the correlation between lipstick wearing between identical and non-identical twins would be near to 100%. This means that the heritability of the trait would be near 0%.