By Ben Blanchard

BEIJING (Reuters) - Hailing "mighty Uncle Xi", Chinese people have taken to social media using an old imperial term to welcome President Xi Jinping's naming by the Communist Party as its "core", despite party efforts to limit his cult of personality.

Following a four-day plenum, the party late on Thursday gave Xi the title "core", putting him on par with past strongmen like Mao Zedong and Deng Xiaoping, though it also signaled his power would not be absolute by underscoring the importance of collective leadership.

While a cult of personality had begun to form around Xi, he has moved to stop practices including adoring songs on the internet and references to him in state media as "Uncle Xi", sources with ties to the leadership say.

Indeed, the party's lengthy communique after the plenum said "boasting" about leaders should be banned and all publicity about them based on fact.

That message has seemingly been lost on enthusiastic users of the Weibo social media service, where posts about Xi praising him as "mighty Uncle Xi" - echoing an expression used to greet an emperor - have appeared despite online censorship blocking searches for the expression.

"With Uncle Xi as the party's core, our Chinese dream will definitely be realized," wrote one user, referring to a broad, vaguely defined policy of Xi's to build a strong and prosperous country.

The Global Times tabloid, published by the party's official People's Daily, said Xi's role as the core "in fact has long been in the minds of the Chinese people".

"All Chinese know clearly that the Xi's leadership has played a critical role in the changes in China in the past four years," it said in an editorial, pointing to the success of his corruption fight and in tackling issues like terrorism.

"It was beyond anybody's belief that corruption could be tamed and officialdom would progress toward less corruption a few years ago. But it is happening in China."

Dozens of senior officials have been jailed in the campaign against graft. Xi has warned the problem is so severe it could affect the party's grip on power.

That has made him immensely popular with ordinary Chinese, even if people who spoke to Reuters on Friday in a traditional hutong alleyway not far from the Zhongnanhai leadership compound were not entirely sure what the term "core" meant.

"He's done things the other leaders could not do, and that's really fight corruption," said deliveryman Wang Hui, 40, who said he had not seen any news about the plenum the night before.

For housewife Cui Huiping, Xi is simply a charmer.

"He's so handsome. Such manly charm. It's very attractive," she said, before hurrying off to do some laundry.

(Editing by Robert Birsel)