Measuring a bicycle chain's pitch can be used to identify chain wear and flag the need for a replacement chain and/or cogs and chainrings. Bicycle Chains: Length, Width, What's Best to Buy etc.
Daith piercing. A Daith piercing (pronounced DÃ¤TH) is an ear piercing that passes through the ear's innermost cartilage fold, the crus of the helix. In most areas this piercing is pronounced day-th which can be compared to the word faith, which is nonstandard. The standard pronunciation is doth like goth.
So, if you follow the logic of this, a Daith piercing represents knowledge guarding the entrance to your ear. Kind of like a filter. The piercing was popularized in Fakir's Body Play Magazine. Also it may have been one of the motivating factors for the development of curved needles which was championed by Erik Dakota.