The phrase "alter the definition" is correct and usable in written English.
You can use it when discussing changes to the meaning of a word or concept in various contexts, such as academic writing or debates.
Example: "In recent years, many have sought to alter the definition of success to include personal fulfillment rather than just financial gain."
Alternatives: "change the meaning" or "modify the definition".
Accepting Turkey as a European Union member would quicken that trend and irrevocably alter the definition of Europe.
At the heart of the conference was the assumption that a group of advocates could alter the definition of dyslexia and what it means to be dyslexic.
"Orange" continues the company's push to compete with traditional sources of entertainment and, along the way, alter the definition of television.
Many employers are lobbying for legislation that would alter the definition and reduce the number of businesses subject to the employer mandate.
In a postmodern and very American way that may alter the definition of Jewishness, many conclude that joining the faith no longer requires crossing the threshold of formal conversion, but is instead becoming a matter of simple self-identification.
In the UK there are about 6m households in fuel poverty, which is set to rise to 9m by 2016, though the government is likely to alter the definition to reduce the headline numbers.
The E.P.A. argues that by altering the definition of "fill" to include waste it is merely legalizing current practice in the coal mining industry.
(Years before Kim Jong-il came to power, the North Korean Academy of Social Sciences altered the definition of hereditary rule in its "Dictionary of Political Terminologies," removing the phrases "a reactionary custom of exploitative societies," "originally a product of slave societies," "adopted by feudal lords as a means to perpetuate dictatorial rule").
Mursaleen et al. [19] have altered the definition of weighted statistical convergence and have found its relation with the concept of statistical ( R, p r ) -summability.
DISCUSSION: The implications of the results include that disability measurement, including altering the definition of being disabled and possibly expanding the state space of a model, may not affect population-based estimates of ALE.
