Obverse vs Reverse

Also known as the heads because it historically depicted the head of a prominent person. Also known as the tails because the tail is at the opposite end of an animal and this side is the opposite side of the head.
Lately commonly shows a ‘national symbol’ ie. Coat of arms, bust of monarch or president. Commonly shows various aspects of a country such as iconic traditions, landmarks, animals and people of that country.
It is also the side of a coin which usually states the year of mintage. It is the side of the coin which usually states the denomination or face value of the coin.