This clumping is spoken of as agglutination and the substances produced in the animal are called agglutinins.

Therefore anthropo-geography, instead of clumping the passes, sorts them out, and notes different relations in each.

He went to the bank building and entered the rear door, clumping heavily up the stairs, for he felt a heavy depression.

The man was clumping slowly along in his rubber boots; an old cap was slewed awry on his head, its peak drawn down over one ear.