Information will be useful for beginners, as he himself recently encountered the definition of the obverse and reverse of different coins.
Obverse (lat. adversus - facing) - the front, the main side of the coin.
In the information that you read, there is no consensus on which side to take for an obverse coin.
Usually, obverse is determined by the following characteristics (if it is not possible to determine by 1, it is determined by 2, etc.):
1 - a portrait of the head of state, monarch, president, deity;
2 - the state emblem or emblem (if on both sides of the coin there are coat of arms, then the obverse is considered the one on which the coat of arms of higher rank is depicted);
3 - a legend with the name of a country or territory;
4 - the name of the issuing bank or a legend with the name of the holder of the right to coinage;
5 - if the coin does not meet all the above points, the obverse is considered to be the side opposite to the face value of the coin;
There may be exceptions, then you need to refer to the catalogs of countries in which coins were issued.
Reverse (lat. revertor - turn back) - the reverse side of the coin opposite to the obverse.
Edge (it. Gurt - belt, belt) - edge of the coin.