Tail Spike or Endpin - This is located underneath the double bass. The function of the endpin is to support the instrument and ensure that it doesn't slip while being played.
Tailpiece - This is located at the bottom of the double bass. Usually made of plastic, it's function is to hold the strings.
F-Hole - The f-hole is called such because it is in the figure of the letter "f." The function of the f-hole is to allow the sound to come out as well as to amplify the sound.
Bridge - This is the part of the double bass that holds the strings. As the strings vibrate, sound travels to the body of the double bass and comes out of the f-hole.
Neck and Fingerboard - Both refers to the long part of the double bass that is attached to the body. The strings are pressed down on the fingerboard while playing.
Strings - This is the part that enables the double bass to produce sound in varying pitches depending on what you press on the fingerboard.
Pegs and Pegbox - The double bass has four (others even five) strings and it is wrapped around a peg. The peg is used to tune or alter the pitch of the double bass.
Scroll - This is located at the top end of the double bass and is also referred to as the ornamental curve of the instrument.