A downloadable program is a type of software that can be downloaded from the internet and installed on a computer or other device. An app, which is a three-letter word for this type of program, is a small application that can be downloaded to a mobile device such as a smartphone or tablet. A podcast, which is a seven-letter word for this type of program, is an audio or video file that can be downloaded from the internet and listened to or watched on a computer or other device.