• 2.54 centimetres.
• As long as this line:
• Half of my index finger!
• The height that a ball must be if it were to fall for 0.72 seconds in a vacuum on Earth before landing.
• A bit of trivia. The typical American dollar is six inches, in case you are ever without a ruler and want to take a quick measurement. So, I guess that makes an inch about 1/6 the length of an American dollar.
• EXACTLY 1/8 THE LENGTH OF MY PENIS.
• Imperial measurements were based on some silly things. An inch was actually the width of the king's thumb. A foot was the length. I'm not quite sure if they changed this measurement everytime a new king was installed. But that is the history of where the inch and the foot come from. I guess kings always had pretty small yards behind the palace. (ha ha ha)
• mushroom
From Old English "gerd" (rod), in the twelfth century, King Henry I decreed that a yard would be the distance from his nose to the thumb of his outstretched arm.
• The original means of measuring the inch is not known, there are many theories. One is that it was 1/12th of the length of the rulers foot (this would have it going back to either Latin or Roman days and be derived from the word ynche). But this caused measurement troubles because each successive ruler had a different sized foot, so latter it became standardized to it's current length.
• In the porn industry, it is almost exactly equal to 1/2 of one standard inch in length. Which probably explains adc's answer! ;)
• Twice as long as the distance from the end of the measurement to the center of the measurement.