The phrase "major thread" is correct and usable in written English.
It can be used to refer to a significant or important topic of discussion or a central theme in a conversation or text.
Example: "The major thread of our discussion today will focus on climate change and its impact on global economies."
Alternatives: "key theme" or "central topic".
The question of readiness has been a major thread running through the Clinton-Obama race.
Self-invention is a major thread in this biography of the witty, passionate liberal columnist, who died in 2007.
Italian has been a major thread through the first three restaurants, because I personally love the cuisine.
"The pursuit of wealth for its own sake -- that is a major thread of our modern consciousness," Mr. Lightman said.
All the books present three linked novellas that set up, wander away from and return to a major thread.
Mr. Jay then pounced on the comment, seeking to connect it to the major thread of his questioning from Wednesday in which he attempted to show that Mr. Murdoch's papers could use newspapers to influence political elections.
Most critics, in fact, will have never seen this latest version before they see one that greatly changes major threads of the story, choreography and songs".
At the same time, Keane leaves some of the major threads of Havel's personal life dangling: the death of Olga, Havel's wife of 45 years and a major figure in the earlier chapters, is appended as an afterthought to a chapter on Havel's second marriage to a young actress.
One of the major threads that emerged after the news of an attack in January on Sergei Filin, the artistic director of the Bolshoi Ballet in Moscow, was just how much ballet matters in Russia, how passionate the fans there are, and how important the Bolshoi is to Russia's national identity.
Besides music, one of the other major threads of my life was the idea of space of this vast galaxy and the infinite black above us.
Finally, after summarizing the growth in three age-group partitions, some of the major threads of development are noted under the heading of continuities from the past and perspectives into the future.
