I would hazard that the unit of such ground of meaninng is the small incremental experiential agreements that are made in the ebb and flow of communication. These agreements are what build a vocabulary in the first place -- settling on tokens to cross-represent experience. In the final analysis it is based not an any absolute frame but on a series of transactions which are brought forward on the strength of trust and a sense of the probability that commonality is within sufficient limits.

Perceptions in time, without that parallel timestream of agreements, may breed a different sort of genius, but the ribs and stays of the culture are agreements. Obviously different cultures have their own pool of agreements for individual morphemic bits, and the degree of intersection is reflected in likeness of cultures, language and genes.

A