the state of being the most important or of coming first in order or rank, the state of being leading or predominant;
e.g. It took him years to achieve primacy as an expert in the field.
(noun)
(psychology) the state of having been introduced to someone/something earlier, describing an object, especially in the context of it being more likely to be remembered;
e.g. These stimuli are subject to the primacy effect, and are thus retained in the memory for longer.