Definitions of gravel:

• noun:   rock fragments and pebbles
• verb:   cover with gravel

  Example: "We gravelled the driveway"

• verb:   cause annoyance in; disturb, especially by minor irritations
• verb:   be a mystery or bewildering to
• adjective:   unpleasantly harsh or grating in sound

  Example: "A gravelly voice"

• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #10904)