党龄

In mainland Chinese usage, 党 by default means the Communist Party (中国共产党), so 党龄 most often refers to CCP membership tenure. Counting starts from the end of the probationary period (转正 of one's status). Often noted in obituaries and biographies as a marker of political seniority.

memory

Same 龄 ('age / length of') pattern as 工龄 (years of work), 教龄 (years of teaching), 军龄 (years of military service), 学龄 (school age).