The term SUBJECT ODE can be broken down into two parts: the word 'SUBJECT' and the acronym 'ODE'. The word 'SUBJECT' is defined as a person or thing that is being discussed, dealt with, or studied. The acronym 'ODE' stands for 'Ordinary Differential Equation', which is a type of mathematical equation that involves derivatives of functions with respect to one or more variables. An ordinary differential equation is used to describe the behavior of a system over time. In summary, the term SUBJECT ODE refers to the study of ordinary differential equations and their applications.