The entry reads (my emphasis added): "1 : the activity or process of learning about something by reading, memorizing facts, attending school, etc. [noncount] ▪ Becoming a doctor requires years of study. ▪ You can improve your knowledge of the natural world by study and observation. ▪ She is engaged in the study of law. [=she is studying law] ▪ You can design your own course of study. [=you can choose the subjects you will study] [plural] ▪ She will return to her studies after vacation. ▪ He left the service to pursue his studies."
The plural form is often used for "a particular person's learning activities, for example at a college or university: to continue/pursue your studies" - ALD