# A string of letters (M-I)

Your goal is to place a 4-letter English word somewhere in the string of letters below. There's only one word that fits.

                MTSEELLIMDTSEITNEGNIUQCTSEMUTNECLTNIGAUQNIUQXTSEMECEDVTSEEUQNIUQITSESUNU


What's the missing word? Explain why.

I think the missing word is

SEAT

Explanation:

There seems to be Latin numerals hiding in there. In particular, I noticed UNUS and QUINQUE reversed at the end, which I guessed were 1 and 5 respectively. So what if we reverse the whole string of letters?

Doing this, we get:

UNUSESTIQUINQUEESTVDECEMESTXQUINQUAGINTLCENTUMESTCQUINGENTIESTDMILLEESTM

And there's a lot of EST's here and Roman numerals (seeing the V and X led me to that thought). Indeed, when we put appropriate spaces, we get:

UNUS EST I QUINQUE EST V DECEM EST X QUINQUAGINT L CENTUM EST C QUINGENTI EST D MILLE EST M

We can see a sequence where the terms are [Latin numeral] + EST + [Roman numeral], and the terms of the sequence are the numbers which can be represented by a single Roman numeral, in increasing order. EDIT: However, thanks to juicifer, I realized that EST is not meant to be parsed on its own (I guessed previously that EST meant "it is" in Latin), but rather each term is a sentence. For example, "unus est I" in Latin means "one is I". (Because of this, at this point I don't mind if juicifer's answer gets accepted despite me coming first, since he was the first to provide an accurate answer.)

But notice that 50 in Latin is quinquaginta, not quinquagint. There's also no "est", so let's add that. In total, we have to add either A + EST (at the end of quinquagint) or TA + ES (between the N and the T).

However, only one leads to a 4-letter English word. Noticing that the original string was reversed, we reverse what we added as well. AEST reversed is TSEA, which isn't a word, but TAES reversed is SEAT, which is a word. And so we have that as our answer!

• ha, you got me by about 30 seconds! nicely done Aug 15, 2023 at 15:20
• hahah thanks, but also props to you too since ROT13( lbh cnefrq gur fgehpgher bs rnpu grez bs gur frdhrapr pbeerpgyl hayvxr zr - V qvqa'g ernyvmr gung "rfg" jnfa'g zrnag gb or cnefrq ba vgf bja ) :)
– oAlt
Aug 15, 2023 at 15:24
• fair enough, though to be completely fair, I assumed that, as I'm not super familiar with the source material (V qvq gnxr serapu va fpubby fb gurer'f ng yrnfg fbzr pbaarpgvba gb yngva yby) Aug 15, 2023 at 15:56
• Well done! Having a hard time deciding who to give the check mark too, wish we could do rock paper scissors :D You were first but like you say @juicifer had the right interpretation of the "is" (that's such a small part of the puzzle though) but other than that both answers are good with the correct missing word so I'm going to give it to you anyways. Aug 15, 2023 at 17:05

The word is

SEAT

Here's why:

The first step is to

reverse the string:

UNUSESTIQUINQUEESTVDECEMESTXQUINQUAGINTLCENTUMESTCQUINGENTIESTDMILLEESTM

This might start to look familiar to some. Let's

UNUS EST I QUINQUE EST V DECEM EST X QUINQUAGINT L CENTUM EST C QUINGENTI EST D MILLE EST M

Now, we can see that this is

a list of the Roman numerals and their equivalent Latin words - e.g. "unus est I" means "one is I". This is also hinted at with the (M-I) in the title, as in its original order, the string decreases from M (1000) to I (1).

We're missing a bit, though - that must be where our word comes in:

QUINQUAGINT is close to the Latin word for fifty, QUINQUAGINTA (no wonder they decided to use L instead!). We're also missing the EST that is found in all the other lines. There are actually two ways to fill in the remaining letters, as that T could belong to either QUINQUAGINTA or EST:

...QUINQUAGIN|TA ES|T L...
...QUINQUAGINT|A EST| L...

but neither TAES nor AEST is a word - even in Latin. But remember, we reversed the string in the beginning. So putting things back into the right orientation:

...L T|SEAT|NIGAUQNIUQ...
...L |TSEA|TNIGAUQNIUQ...

And of course, TSEA is not a word, but SEAT is!

Here's the full string:

MTSEELLIMDTSEITNEGNIUQCTSEMUTNECLT|SEAT|NIGAUQNIUQXTSEMECEDVTSEEUQNIUQITSESUNU

• Well done! Like I said under @oAlt answer, rock paper scissors would've solved this :) Both answer are good but im going to give it to oAlt since they answered first (although the minor error "is"). Unfortunately we can't give two check marks but great job anyways! Aug 15, 2023 at 17:07
• @Prim3numbah, no worries! it was a fun solve, and isn't that its own reward Aug 15, 2023 at 17:12