Erudition comes from Latin through Middle English. A scholar is erudite (Latin eruditus) when instruction and reading followed by digestion and contemplation have effaced all rudeness ("e- (ex-) + rudis"), smoothed away all raw, untrained incivility. Erudition is the depth, polish and breadth that is applied to education from further readings and understanding of literary works. The Latin word educare means to "lead out" from ignorance. The educated person has been led to think critically and with logic. The erudite person has additionally become familiar with some more arcane information, has a deeper familiarity with the literature on the subject and a broader intellectual horizon.
An erudite person will gain insight on particular subjects through books and study, rather than by following a course or scholarship in the subject. The famous Italian poet Giacomo Leopardi was erudite: he read and studied the classics on his own, and was deeply influenced by many philosophers. Among the most erudite of Roman writers was Marcus Terentius Varro. Among the most erudite English essay-writers is Sir Thomas Browne.
A jurist who is learned, knows the law intimately and thoroughly; an erudite jurist also knows the history of the law in detail, and the law of other cultures.
Erudition is recognizable and reflected in a literary work since an erudite writer will usually have a general knowledge spanning different fields. Such a universal scholar is sometimes called a "polymath."