CAT

This is the most frequent question asked when one starts preparing for CAT. CAT is a test with no predefined syllabus, however past trends suggest that CAT tests in general aptitude including Verbal Ability (English), Quant Ability (Mathematics), Logical Reasoning (LR) and Data Interpretation (DI) skills.
Similar to CAT, there are other admission tests - MAT, XAT, CMAT and SNAP. There are some B-Schools (like IIFT and IRMA) which conduct their own exam. And there are state level entrance tests for admission to colleges in respective states.
CAT English/Verbal Ability: Reading comprehension, verbal reasoning, syllogisms, analogies, antonyms and synonyms, fill in the blanks, sentence correction, idioms, etc.
CAT Maths/Quant Ability: Number systems, geometry, trogonometry, probability, permutation combination, algebra, mensuration, time and work, averages, percentages, profit and loss, quadratic and linear equations, etc.
CAT Data Interpretation: Interpretation and analysis of data based on text, tables, graphs (line, area), charts (column, bar, pie), venn diagram, etc.
CAT Logical Reasoning: Clocks, calendars, binary logic, seating arrangement, blood relations, logical sequence, assumption, premise, conclusion, linear and matrix arrangement, etc.