Coin orientation
Coin orientation (or coin alignment or variations of these) is a feature of coins struck by some nations. In these nations, most coins, including all modern coins, have their reverse turned, or aligned, in a specified way relative to the obverse. There are essentially two options, referred to as medallic orientation and coin orientation.
Medallic orientation
Medallic orientation (or medal alignment, or variations of these) derives its name from medals tagged to a uniform. For a medal to display properly, even if it flips over, the reverse needs to be aligned so that the top of the reverse shares the same position as the top of the obverse. In other words, the image on one face of the coin is rightside-up relative to the other.
In Britain this is sometimes referred to as "British turnover".
Coins with medallic orientation include British coinage and most other Commonwealth coinage, Japanese yen coinage, and euro coinage.
Coin orientation
The opposite situation is seen in some coins, e.g. coins of the United States. In this case, the coin must be flipped about its horizontal axis in order to see the other side the correct way up. In other words, the image on one face of the coin is upside-down relative to the other. For this reason, 'coin orientation' is used in the United States to express the opposite of 'medal orientation'.
Coins with coin orientation include United States coinage, South Korean coinage, Thai coinage and pre-Euro French coinage.