No-one seems to have the definitive answer for the origin of the word "iPod". All seem to agree that the "i" stands for Internet, as it was developed from a device to capture files over the 'Net. The "Pod" part has been variously explained as a pod as in pea-pod, a small thing but stuffed full of content, and letters derived from Personal On Demand, in the sense that the iPod owner decides what to put in it, and as a download idea "download on demand" was a buzzphrase a few years ago.
In any event it is a jealously guarded trademark of Apple Computers. A protective cover called "Tightpod" was the subject of restraint by Apple.
However, the Company is happy to have all and sundry advertise their device by the common use of the word "podcast", being a audio file containing the content or extracts from a previously broadcast TV or radio programme, or a specifically designed product for the medium.
The potential user does not need an iPod to use to these files, but by not objecting to the use of the word, Apple fosters the wrong opinion that the public need to rush out and donate to the Apple Computer Company coffers.