In 1956, Benjamin Bloom published a hierarchy for categorizing educational goals. This hierarchy was titled Taxonomy of Educational Objectives. The taxonomy is a hierarchical classification of different levels of thinking. Bloom's taxonomy was updated in the 60s and 70s and revised by Anderson and Krathwohl in 2001.
The framework for the taxonomy contains six major categories: Knowledge (Remembering), Comprehension (Understanding), Application (Implementing), Analysis (Interpreting), Evaluation (Assessing), and Synthesis (Creating).
Within each of these six categories, there exists a continuum from simple to complex and concrete to abstract.
See the image for examples of ways each of the six categories could be applied to instruction.