The phrase "in crowds of" is correct and usable in written English.
You can use it when talking about a situation involving a lot of people, especially in a busy or public place. Example Sentence: We had to push our way through in crowds of people to get to the front of the line.
They reduce us all to random faces in crowds of strangers.
Newcastle United's ground dominates the city's skyline and regularly pulls in crowds of over 50,000.
Social media postings suggested that some injuries might have occurred when people were trampled in crowds of protesters.
When your job is being in crowds of people and touring with people, being alone is a luxury.
Amongst these are discovering visual information that is implicit in experts' brains and in crowds of people and estimating its accuracy.
I like being caught up in crowds of tourists or shoppers, hearing languages from German and Hindi to New Jerseyese.
Today, Feedly is taking a big step toward joining the "in" crowd of magazine-style applications, with a dramatic redesign of its mobile apps for iOS and Android.
Don't do anything too crazy, just try to blend with the "in" crowd of your school.
And there is wisdom in crowds, even--perhaps I should say especially--in crowds of volunteers and amateurs.
Response to this wave of craft spirits from consumers abroad has been overwhelming: Where the in-crowds of Berlin and Hong Kong might have previously asked for a Grey Goose vodka or a Macallan single-malt Scotch, today more drinkers are demanding a Balcones whiskey from Waco, Tex., or a Perry's Tot gin from Williamsburg in Brooklyn.
When he moved to London in the 1980s, he became linked with the rising in-crowd of Young British Artists (YBAs).
