Some nouns are constructed from two words joint together, as in 'football', 'playground', 'gatekeeper'. These are sometimes labeled closed compound or solid compound nouns (Wiktionary, Oxford dictionaries, Collins).
It is possible to create even longer compound nouns such as 'football playground gatekeeper", but this isn't a closed compound anymore. Contrast this with German, in which compounding to a single long word is more common (in the past this could be used to create extremely long words... though nowadays they are usually separated in writing).
I'm looking for examples of English closed compound nouns built from more than two words, but I can't think of anything. Does it occur at all?
Update: after finding no such word, and getting some feedback here, I suspect that English closed compounds are always constructed from exactly two words (?) (Well, except for ManBearPig, that is...)
For example, this reference puts the first and second words in two columns of a table, and there's no third column.
However, I found no such explicit rule anywhere.
What I'm looking for is either (1) a rule similar to the above, in some reliable source; or (2) a counter-example (strictly closed compound nouns, no spaces or hyphens, three or more words).
(If I don't find either one, I will suggest that as a new English language rule!)