Some words

There's an old word square that has the Latin words:

SATOR
AREPO
TENET
OPERA
ROTAS

I was reminded of this when watching the film Tenet. I probably originally learned it from Corto Maltese or something.

The point of the thing is that you can read each of the words either way and they fit that 5x5 square, with a palindrome in the middle.

Reading from Wikipedia, the significance of some words is a bit questionable. It might be there is a forced fit with AREPO, which apparently means nothing as such.

One nice convenient explanation says the square was likely a way to hide PATERNOSTER A O A O (Alpha Omega) for early Christians.

Then I begun to wonder, if there were other such squares possible in English language (dared not to go to Finnish yet).

After struggling with the impossibility of doing it manually, I turned to Processing.

Obviously I just could have looked the results, probably it has been thought over a zillion times. But, nah, I wanted to try it out myself.

First I needed a dictionary. From the web I could find a word list of 5-letter English words (this one), and then another. The shorter list had a couple of words the longer list didn't, so I combined them to a longer list of 9168 words.

I then generated a list of palindromes using Processing. The result was these 26 words:

1:level
2:refer
3:radar
4:madam
5:rotor
6:civic
7:sexes
8:solos
9:sagas
10:kayak
11:minim
12:tenet
13:shahs
14:stats
15:stets
16:kaiak
17:finif
18:dewed
19:alula
20:deked
21:deled
22:semes
23:seres
24:stots
25:sulus
26:torot

Next I made a list of reversable words (that could be found on the same list), but were not palindromes. There were 181 such words, but I'm not going to list them here.

Using the palindromes in the centre, it's a simple and fast task to check if there are words from the reversible-list that would fit together with the palindrome.

Step 1: Start from a palindrome in the list.

..1..
..1..
11111
..1..
..1..

Step 2: Check if the center letter of any of the reversed words fits the first letter of the centre palindrome. The start and end letters don't matter.

22?22
..1..
11111
..1..
..1..

If so, for this word, check the reverse word list again for words where the first letter fits the word in step 2, and shares also the centre letter with the second letter of the palindrome.

(The first letter of the third word should be compared with the fourth letter of the 2nd word, too.)

2?222
.31..
1?111
.31..
.31..

If these conditions are satisfied, the word square should be acceptable.

There are a lot of squares that get to this stage:

REMIT
E I I
MINIM
I I E
TIMER

For example, REFER has the following possibilities (including reverses) for the edges: parts, straw, fires, ports, cares, strap, serum, warts, scram, sirup, mural, serif, tarps, strop, sprat, tared, sprog, worts, airts, arris, derat, gorps, korat, lares, larum, marcs, mures, puris, saros, serac, seral, sirra, soras, stria, strow, tarok

Especially palindromes REFER, RADAR, ROTOR and ALULA have a lot of potential, so I guess just looking and Googling obscure words might get to a result. Not everything is in that dictionary.

DECAL
E I A
CIVIC
A I E
LACED

For the above I did google for AVISE, which is not on the word list at all, and yet there is such a word. But ESIVA does not seem to mean anything. Turns out there are quite many solutions with the third word working in one way, but almost none reversible.

Also, the point was to use the computer to calculate the word lists.

From the original list of 9000+ words, only one full combination could be found:

DEFER
ELIDE
FINIF
EDILE
REFED

Even that is not so impressive, considering the words around the edges have E two times and the inner words also have two Es.

Are those words really even English? They are in the dictionary, though.

Defer is the most normal word here: to put off, to postpone.
Refed is a past participate of refeed, e.g. the dog was refed, which makes sense once explained.
Elide: To suppress or alter by ... elision. (The omission of a sound or syllable when speaking)
Edile is a variant spelling of aedile, meaning a magistrate in ancient Rome.
Finif is an obsolete slang word coming from Yiddish, used to mean a "five-dollar bill".

It should be much more time-consuming to find out all the ways in which the square could be filled with the dictionary, crossword-style, if at all. Perhaps some other time...