x1 is an ordered series of podcast episodes/podcast serial, ordered by conparison rule x2 (contextless default: production order or intended listening order, or reverse of these), and being entirely composed of all of the individual episodes belonging to set x3.
Technically, any sequence of any podcast episodes is such a thing. Moreover, some podcasts are just a collection of episodes which have no intended listening order (if old episodes are meant to be listened to at all). However, this word is meant to encompass only canonical serial productions of closely related episodes in a certain listening order. Thus, a playlist on shuffle breaks the spirit/intent of this term but not its technical definition; every episode in a certian program, though, satisfies the intention (especially if x2 is a reasonable listening order thereof) - although complications arise if there is no reasonable listening order to be endowed upon the set of episodes. This word uses a rafsi of an experimental gismu: kicra.