"RCA" connectors are found on the back of nearly every consumer DVD player and other home electronics devices.
This may seem really mundane, but understanding audio connectors is important to the production process. There are four basic types of connectors: RCA, Phone, Mini and XLR. It is important that you are able to identify each.
"Mini" jacks are the kind your earbuds have on the end. There are increasingly popular today as everything gets smaller.
In the old days, the "phone" connector was used to patch phone calls--hence the name. Phone connectors are still used today--especially for microphones (and guitar amps!).