DEFINITION: it means to contribute (give) to something or someone or to join in.
EXAMPLE: Dad wants everyone to pitch in this weekend and help clear the backyard.
Make a pitch for
DEFINITION: it means to make a presentation to influence others to support, purchase, or agree to something.
EXAMPLE: Wanda will be making a pitch for her new product idea at the meeting today.
DEFINITION: it means completely or extremely black.
EXAMPLE: The stars were covered by clouds, and there were no lights for miles, so it was pitch dark all around our campsite after we extinguished the fire.