What's a concertina word?

A concertina word, word Z, is a word in English which can be formed from splicing together two other English words, word X and word Y, such that the letters of word X form the odd numbered letters of word Z, and word Y, the even ones.

It might be simplest to explain with a simple example:

The words FRIENDS is a concertina word because it can be formed from the words:

    F I N S
and  R E D

While the prize ('what prize' I hear you ask) goes to the longest word, bonus points ('what bonus points') are on offer for interesting answers - for instance, where words x, y, and z make a plausible phrase, or where the subwords resonate with the meaning of the superword.

Rosie F advises that this sort of construction is actually called an alternade q.f. https://en.wikipedia.org/wiki/Alternade (although I like my term better).

  • 3
    $\begingroup$ This sounds like an interesting candidate for code golf! $\endgroup$
    – Doddy
    Oct 21, 2016 at 7:37
  • 4
    $\begingroup$ I’m voting to close this question because without defining "word" it turns into an ill-defined, open-ended puzzle (and open-ended puzzles are off-topic as of May 2019) $\endgroup$
    – bobble
    Oct 11, 2022 at 16:41

4 Answers 4


A computer search finds


though it's not a great word. (A web search does find at least one place -- a technical article -- in which it is used.)

The computer search, starting with a big wordlist, went like this:

words = set(open(___filename of wordlist___).read().split())
def is_concertina(w): return w[::2] in words and w[1::2] in words
good = {w for w in words if is_concertina(w)}
m = max(len(w) for w in good)
list((w,w[::2],w[1::2]) for w in good if len(w)==m)

which returns the example above and no others. So if you don't like the long word there, we'd better look at shorter ones; here are the two that were found with the length reduced by 1:


  • $\begingroup$ That's a great one (maybe the greatest?). Care to explain your method? (I really don't understand how you managed to complete this task within a minute of my asking ;-) ) $\endgroup$
    – Strawberry
    Oct 20, 2016 at 13:02
  • $\begingroup$ I'll put some details into the answer. $\endgroup$
    – Gareth McCaughan
    Oct 20, 2016 at 13:07
  • $\begingroup$ Done; I also give a couple of shorter examples (there are no others of equal length with my wordlist), at least one of which is I think perfectly convincing in that no one could question whether any of the things it uses is a "real" word. $\endgroup$
    – Gareth McCaughan
    Oct 20, 2016 at 13:14
  • $\begingroup$ unporousness: The lack of pores. $\endgroup$
    – EKons
    Oct 20, 2016 at 14:22
  • 1
    $\begingroup$ Well found. For the benefit of researchers present and future, such a word is called an alternade. $\endgroup$
    – Rosie F
    Oct 20, 2016 at 15:27

Some for the fun/phrase category:

Peewee's ewe pees
Clips Calliope's aloe
Pro-parrot art
Lord Bloodred bode
Sauteed, ate, sued
Ones countess cuts
Sand tie stained
Weirdoes: wide eros

  • 5
    $\begingroup$ I love sauteed, ate, sued. A sand stained tie is also a nice idea. $\endgroup$
    – Strawberry
    Oct 20, 2016 at 15:47

Perhaps a nod to a recent conspiracy theory (of at least one individual)

If you combine POLLS and EPEES you get PEOPLELESS

Not as long as any of Gareth McCaughan's but obtained with a similar method.

  • 7
    $\begingroup$ Used carelessly enough, I suppose epees can produce peopleless polls. $\endgroup$
    – Strawberry
    Oct 20, 2016 at 16:31

Going for the bonus, putting the long word first or last which seems in keeping with the spirit of the question (though it doesn't help much in the middle):

    C L A S S
     O L P E

For 9 is the longest plausible sentence I can find with the long word first or last. According to Wiktionary an olpe is Originally, a leather flask or vessel for oils or liquids; afterward, an earthenware vase or pitcher without a spout

For common words:

    S O L D
     P I E

For a mere 7.

  • $\begingroup$ This used Gareth McCaughan's approach (and indeed a modified version of his code). $\endgroup$
    – Chris H
    Oct 20, 2016 at 15:25
  • $\begingroup$ I particularly like sold pie spoiled $\endgroup$
    – Strawberry
    Oct 20, 2016 at 15:43
  • $\begingroup$ @Strawberry I nearly answered with just that but managed to extract a sentence from a longer combination at the last minute $\endgroup$
    – Chris H
    Oct 20, 2016 at 15:45

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