The phrase "a main area of" is correct and usable in written English.
It can be used to refer to a significant or primary focus within a particular context or subject matter.
Example: "The research team identified a main area of concern regarding the environmental impact of the project."
Alternatives: "a primary focus of" or "a key aspect of".
Minors can either counterbalance or complement a main area of study.
A main area of public concern was Technical Area 55, where the laboratory keeps most of its nuclear materials.
The Donetsk airport has remained a main area of contention despite the ceasefire that has been violated by both sides.
The effort directly challenges a main area of growth for some of Cisco's big customers, including I.B.M., Oracle and most pointedly, Microsoft.
A main area of concern, critics contend, is that the recipients must take anti-rejection drugs for the rest of their lives.
Bank recapitalization, the third pillar of the October meeting, was not a main area of discussion on Tuesday, but there are worries that this requirement may impose burdens on banks that make them less likely to lend.
As a physician, whose main area of research is preventing and reversing many of the degenerative conditions associated with "normal" aging, I know the dangers of stress.
Mr. Dominguez, for example, is an agronomist whose main area of expertise is spoiled food and who has to make do with a staff of just 20.
Taking a step back, the main area of LiveFyre is the key to discovering what to talk about on the site.
Sewell, who proudly proclaimed that he was "neither liberal nor broad-minded", was an art historian whose main area of expertise, honed in his years at Christie's, was old master paintings, particularly 17th-century Dutch art.
To combat this, I have always tried to develop an Internet-based interest that runs at a right angle from my main area of endeavor.
