The term 'Central Line' refers to a medical procedure in which a thin tube is inserted into a patient's body, usually through the chest wall, to provide access to the bloodstream for medications, fluids, or other treatments. The crossword solutions for this term are 'DIAMETER' (8 letters), 'AXIS' (4 letters), and 'Axial' (5 letters). DIAMETER is the length of a straight line passing through the center of a circle or sphere. AXIS is an imaginary straight line about which a body rotates. Axial refers to something that is related to or situated around an AXIS.