The term CAL.UNIT can be broken down into three parts: SEN (3 letters), TECH (4 letters), and JAN (3 letters). SEN stands for 'SENIOR', which is a title given to someone who has achieved a high level of experience or authority in their field. TECH stands for 'TECHNICIAN', which is a person who is trained to use specialized equipment and tools to perform technical tasks. Finally, JAN stands for 'JANITOR', which is a person who is responsible for cleaning and maintaining a building or area. Together, these three terms form the acronym CAL.UNIT, which stands for 'SENIOR TECHNICIAN Janitorial Unit'. This is a unit of personnel that is responsible for providing janitorial services in a particular area.