Learn English – What’s a word for a “cultural truth”

Another option would be hand-dominance or hand-dominancy as a single word. It is not as common as handedness and I usually see it in medical contexts. (It is usually in two words but you can hyphenate to form a hyphenated compound noun).

Research shows that hand dominancy can be an important feature affecting one's tolerance of pain. According to a 2009 Israeli study from the University of Haifa, right-handed people are more tolerant of pain than left-handed individuals.

_{Understanding Pain: An Introduction for Patients and Caregivers By Naheed Ali, Moshe Lewis}

It might encompass the left-hand-dominance and right-hand-dominance better than handedness. Handedness can be better understood as a broader term that covers mixed-handedness and ambidexterity also.

They are mentioned as synonyms in some contexts but here is an explanation of the differences between hand dominance, handedness and hand preference:

Hand dominance means that one hand has the most influence or control. Handedness means that one hand is more reliable for use across a range of skillful acts. Hand preference means that one hand is preferred or chosen.

_{www.erhardtproducts.com}

Additionally, there are eye-dominance and ear-dominance; and there is the hypernym side-dominance that covers all different types of dominance.

Frame of reference

1.A set of criteria or stated values in relation to which measurements or judgements can be made.
‘the observer interprets what he sees in terms of his own cultural frame of reference’

1.1 A system of geometric axes in relation to which measurements of size, position, or motion can be made.
Oxford Living Dictionaries

With respect to the first example sentence given ("his own cultural frame of reference"), this is related to moral or cultural relativism/absolutism.

In the second mathematical definition it means that measurements can be taken from different points of reference, for example, absolute and relative coordinates. If you have a square on a screen it may begin at coordinates (200, 200), but another square inside that square might have absolute coordinates of (300, 300) but relative coordinates of (100, 100), relative to its parent square.