thin out

English Wikipedia has an article on:

Thinning

Wikipedia

thin out (third-person singular simple present thins out, present participle thinning out, simple past and past participle thinned out)

1. (transitive) To make sparse; to remove some of a group of newly-planted plants in order to allow the remaining ones to grow unimpeded.
2. (intransitive) To become sparse.
   • 1975, Bob Dylan (lyrics and music), “Tangled Up in Blue”, in Blood on the Tracks:

     And later on, when the crowd thinned out / I was just about to do the same / She was standing there in back of my chair / Said to me, "Don't I know your name?"

   • 2009 October 29, David Walliams [pseudonym; David Edward Williams], Mr Stink, London: HarperCollins Children’s Books, →ISBN:

     “Abandon Starbucks!” screamed a member of the staff, and his colleagues immediately stopped making coffees or bagging muffins and ran for their lives
     “It seems to be thinning out a little, ” announced Mr. Stink

   • 2020 December 2, Paul Bigland, “My weirdest and wackiest Rover yet”, in Rail, page 68:

     The numbers thin out the further we get from London, so I don't feel guilty when I remove my mask momentarily to scoff some of the snacks I'd bought at Marylebone.

• prethin