The phrase "define a challenge" is correct and usable in written English.
It can be used in any context where you are asking someone to explain or clarify a difficult situation or obstacle that must be overcome. For example, you could say: "We need to define a challenge that we can work together to solve."
To define a challenge, I needed a goal, and the more I thought about the way our family eats, the more clear that goal became: take the junk food off the regular menu, and return it to the "treat" category.
But it is a great promotional reference for ChallengePost, and the company can charge for extra services, such as consulting around how to define a challenge "There will be additional services that have a price," confirms CEO Brandon Kessler.
The ALA defines a "challenge" as a formal, written complaint filed with a school or library about a book's content or appropriateness.
The ALA's Office for Intellectual Freedom defines a challenge as "a formal, written complaint, filed with a library or school requesting that materials be removed because of content or appropriateness".
The American Library Association defines a challenge as a "formal, written complaint filed with a library or school requesting that materials be removed because of content or appropriateness".
Reconciling all those different impressions of who Mr. Obama is and what he stands for may prove as defining a challenge as fixing the economy.
And how do researchers define an ethical challenge?
As in any other non-pharmacological treatment trial is it always a challenge to define a proper control group.
5 These challenges define a need for additional combinations of therapeutics, ideally targeting complementary steps of the viral life cycle, with improved efficacy and safety.
It is a matter of semantics as well as a great challenge to define a true negative example when it comes to mature miRNAs.
In their update [ 1], those authors define a much broader array of challenges for the future.
