Bloom’s Taxonomy

"Taxonomy” simply means “classification”, so the well-known taxonomy of learning objectives is an attempt (within the behavioral paradigm) to classify forms and levels of learning. It identifies three “domains” of learning (see below), each of which is organized as a series of levels or pre-requisites. It is suggested that one cannot effectively — or ought not try to — address higher levels until those below them have been covered (it is thus effectively serial in structure). As well as providing a basic sequential model for dealing with topics in the curriculum, it also suggests a way of categorizing levels of learning, in terms of the expected ceiling for a given program. Thus in the Cognitive domain, training for technicians may cover knowledge, comprehension and application, but not concern itself with analysis and above, whereas full professional training may be expected to include this and synthesis and evaluation as well. 

The model above is included because it is still common currency, but Anderson and Krathwohl (2001) have made some apparently minor but actually significant modifications, to come up with:

Revised taxonomy of the cognitive domain
following Anderson and Krathwohl (2001)

Note the new top category, which is about being able to create new knowledge within the domain, and the move from nouns to verbs.