The term "career soldier" refers to someone who has pursued a lifelong career in the military and advanced through the ranks. There are several synonyms for this term including professional soldier, lifer, military professional, enlisted careerist, and career military personnel. These terms are often used interchangeably to describe individuals who have served in the military for an extended period of time and have made a commitment to their careers. Other related terms may include career officer, career enlisted member, or senior noncommissioned officer. Regardless of the term used, career soldiers are an essential part of the military system and play a critical role in maintaining national security.