Definitions of felt:

• noun:   a fabric made of compressed matted animal fibers
• verb:   change texture so as to become matted and felt-like

  Example: "The fabric felted up after several washes"

• verb:   cover with felt

  Example: "Felt a cap"

• verb:   mat together and make felt-like

  Example: "Felt the wool"

• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #10633)