broadcast vs podcast

broadcast is a noun but podcast is not a noun.

Word	Noun	Adjective	Verb	Adverb
broadcast	Yes	No	Yes	No
podcast	No	No	Yes	No

As verbs, podcast is a hyponym of broadcast; that is, podcast is a word with a more specific, narrower meaning than broadcast:

broadcast: cause to become widely known
podcast: distribute (multimedia files) over the internet for playback on a mobile device or a personal computer

Other hyponyms of broadcast include sow, generalise, generalize, popularise, popularize, vulgarise, vulgarize, carry, run.

broadcast (noun)	podcast (noun)
message that is transmitted by radio or television
a radio or television show

broadcast (verb)	podcast (verb)
cause to become widely known	distribute (multimedia files) over the internet for playback on a mobile device or a personal computer
broadcast over the airwaves, as in radio or television
sow over a wide area, especially by hand