Typical audio, video connections for conneccting your stereo system to the earphone, tv to the stereo and computer output to the stereo system...
When you know the names of these connections, it will be easier to tell anyone what exactly you want rather than playing pictionary with the other person...
To know more about the pictured connections,http://en.wikipedia.org/wiki/TRS_connector
The RCA connectors
A more exhaustive and classified connections with symbol and uses is given here: