ἐν ξηρῷ → in a dry manner, drily, in the dry

[David N]

Hi everyone,
 I am looking to the correct definition of the ancient Greek term ἐν ξηρῷ in relation to expression: "drystone construction" as mentioned by Aristotle and, If I'm not mistaken, used as an architectural term in the modern (Greekish) form En Xiro. I have no reference for the original text and found the phrase in an article in "Greece is" in Greekish.

 It is a beautiful phrase but very difficult to breakdown the meaning or linguistic formation of the combined words, asides from the basic definitions of: ἐν = preposition for "in" and ξηρῷ = "dry "(used as a verb or noun?). The words combined meaning "in dry" ... which is where I get confused. Does the context in the rest of paragraph dictate its meaning as a structure or method of construction, or do the accents on the characters imbibe the phrase "ἐν ξηρῷ" with it's definition as a standalone term? I have seen the same expression used in many varying contexts but I have noticed that the accents in many cases are different, not there, or a slightly different spelling, so this has left me, well,  quiet bewildered.

Many thanks in advance,

David N

[spiros]

you can understand as: in a dry manner, dryly, following a dry process

The dative is is used for three purposes:
as the indirect object of a verb
how or with what something is done.
relationships of place where and time when
https://daedalus.umkc.edu/FirstGreekBook/JWW_FGB3.html

As for Aristotle, I can find this:

εἰ οὖν ὕλη πᾶσι τοῖς σώμασι τὸ ὑγρὸν καὶ τὸ ξηρόν, εὐλόγως τὰ μὲν ἐξ ὑγροῦ καὶ ψυχροῦ συστάντα ἐν ὑγροῖς ἐστί, [καὶ εἰ ψυχρά, ἔσται ἐν ψυχρῷ,] τὰ δ᾿ ἐκ ξηροῦ ἐν ξηρῷ.

If, then, the matter of which all bodies are composed is the wet and the dry, naturally that which is constituted of wet and cold lives in water [and if it is cold, will live in the cold], but what is constituted of the dry will live in the dry.
— ARISTOTLE, Parva Naturalia. On Respiration, 477 b

[Melbourne]

It may help also to note the following which has a similar ὑγρῷ / ξηρῷ juxtaposition, though here the ξηρῷ is arthrous:

Luk 23:31 ὅτι εἰ ἐν τῷ ὑγρῷ ξύλῳ ταῦτα ποιοῦσιν, ἐν τῷ ξηρῷ τί γένηται;
(For if men do these things when the tree is green, what will happen when it is dry?" NIV).

The accents don't imbue the phrase "ἐν ξηρῷ" with its definition as a standalone term, and the different spellings (and accentuation) likely reflect different inflections showing differences in case, gender, and number. So, for example, the feminine τὴν ξηρὰν is used to mean "dry land" in the following:

Mat 23:15b περιάγετε τὴν θάλασσαν καὶ τὴν ξηρὰν
(You travel over land and sea - NIV)