knick ‧ er ‧ bock ‧ ers /ˈnɪkəˌbɒkəz $ ˈnɪkərˌbɑːkərz/ BrE AmE noun [plural]
[ Date: 1800-1900 ; Origin: Diedrich Knickerbocker , name invented by Washington Irving for the supposed writer of his History of New York (1809), who is shown in the book wearing such pants ]
short loose trousers that fit tightly at your knees, worn especially in the past