Match 3 games are a sub-genre of puzzle games in which your objective is usually to place in a row three gems of a matching color. Matching games tend to involve pairing things of similar appearance by picking them out of an otherwise uniform crowd.
Think cards all face down or some variation of that to imagine what a match 3 game looks like in practice. Relying upon memory as well as a bit of luck, players who can match two things of like origin must then add a third.
This third matching adds to the complexity of a match two game but also allows for a lot of variety in terms of skill emphasis. Matching two things together takes a lot less memorization than three things, after all, and matching three like objects makes the element of chance less important.
These games can be played solo, cooperatively, or competitively and are found not only in video games but also are popular with board games and other card games as well.
The mechanic is quite simple but found in a lot of different puzzles across the genre. Though rarely a game by itself, matching games are found in everything from first-person shooters to visual novels.
Some of the most well-known match three games today are Candy Crush, Zuma, and Angry Birds POP!.
These games make you line up gems or tokens until three alike are in line and able to vanish from the screen.
In this way matching games mimic the mechanics of Tetris but, again, due to their simplistic and exportable nature, can take on many different forms whether it is a matching card game or something like Bejeweled.