Arbitrary (and usually incorrect) units of measurement used mostly by males. Derives from men overestimating their penis size. Dick inches are much shorter than actual inches. Hence a guy can claim to have a 9 inch penis when it is actually closer to 5-6 inches. The term "dick inches" is usually used when over-estimating non-penis measurements.
fellow one: "Finally! There's a parking spot!"
fellow two: "No way, man...You can't park within 30 feet of a stop sign."
fellow one: "There's plenty of room."
fellow two: "Yeah, only if you're measuring in dick inches."
A unit of measurement commonly used by men when measuring the lenght of their manhood. Usually, 1 dickinch is equal to approximately .25 in or approximately 1cm. Thus, a dickinch is an exagarated unit of measurement used to make items sound larger than they truly are.
Shorty, is only 2 inches long, however, he claims to be 8 inches long, obviously, he is measuring by the dickinch.