Pod is the "case" in wich a pea is encased (as an illustration, think in our "feijão verde" pod would be the "vagem" in wich the "feijão'' dwells.

    Broadcast(ing)= Have to do with communication; airing news, programms, music etc.

   So Pod + Cast.    Connected the dots?

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    "i" reffers to internet-related things, gadgets etc.

     So, I-Pod means that you have a Pod that some way  can connect to computers or can receive musics and data coming from the web through a PC. 

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   Explained with a degree of awkwardness, for I am not a technician; I tried focuse on the language aspect only.  But I hope it helps somehow.