verb

• (usually academic, transitive, intransitive) To review materials already learned in order to make sure one does not forget them, usually in preparation for an examination.
  "Students are expected to start studying for final exams in March."
• (academic, transitive) To take a course or courses on a subject.
  "I study medicine at the university."
• (transitive) To acquire knowledge on a subject with the intention of applying it in practice.
  "Biologists study living things."
• (transitive) To look at carefully and minutely.
  "He studied the map in preparation for the hike."

noun

• (music) A piece for special practice; an etude.
• (academic) An academic publication.
  "That new study on noncommutative symmetries looks promising."
• (chess) An endgame problem composed for artistic merit, where one side is to play for a win or for a draw.
• (obsolete) A state of mental perplexity or worried thought.
  "wel said the kynge thow mayst take myn hors by force but and I myȝte preue the whether thow were better on horsbak or I / wel said the knyght seke me here whan thow wolt and here nygh this wel thow shalt fynde me / and soo passyd on his weye / thenne the kyng sat in a study and bad his men fetche his hors as faste as euer they myghte"