to make a study of: to undertake an examination or investigation of; to devote oneself to the study of.

intransitive. To pore carefully over a book.

intransitive. To linger over (a meal, a drink, etc.) while sitting. Also: to be occupied with (a book, or other matter) while sitting.

intransitive. U.S. to mouse over: to pore over (a book). Obsolete.

transitive. To study or investigate completely; to work through. Obsolete. rare.

intransitive. slang (originally U.S.). To apply oneself assiduously or determinedly to a task, esp. studying (frequently with down, away, etc.)…

transitive. To investigate or study systematically; to do research on. Cf. to work out 9 at phrasal verbs 1, to work up 4d at phrasal verbs 1. rare.

transitive. To improve or refine one's knowledge of (a subject); to master by careful study or research. Now archaic and rare.

transitive. To learn (a subject, book, etc.) by hard or concentrated study. Usually with up.

intransitive. To work hard at one's studies; to ‘bone up’. Also transitive, to ‘get up’, ‘mug up’ (a subject); more rarely, without up.