The story
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: The share (portion) of one's mind or headspace that has been garnered by a concept; the amount of attention or awareness that a concept gets in one's mind, especially in competition with the many other potential objects of attention, given the limits and opportunity cost of one's attention. Full definition →
Etymology from Wiktionary, CC BY-SA 4.0.