seniority

This term describes a hierarchy based on time served or age, often carrying a connotation of earned privilege or institutional authority. It is frequently used in professional, military, or unionized environments to determine the order of promotions, layoffs, or benefit allocations. As an uncountable noun, it refers to the abstract quality of being senior. It does not have a plural form in standard usage, as it describes a status or a system of ranking rather than a countable object.