From The American Heritage Dictionary of the English Language (as quoted by Dictionary.com):
Paradigm first appeared in the English in the 15th century, meaning “an example or pattern,” and it still bears this meaning today: Their company is a paradigm of the small high-tech firms that have recently sprung up in this area. For nearly 400 years paradigm has also been applied to the patterns of inflections that are used to sort the verbs, nouns, and other parts of speech of a language into groups that are more easily studied. Since the 1960s, paradigm has been used in science to refer to a theoretical framework, as when Nobel Laureate David Baltimore cited the work of two colleagues that “really established a new paradigm for our understanding of the causation of cancer.” […] Applications of the term in other contexts show that it can sometimes be used more loosely to mean “the prevailing view of things. […]”