The first meaning of «λόγος» necessarily comes forth from «λέγω», that is, collection, assembly, gathering. We read in Homer: “let us collect (λέγωμεν) the bones of Patroklos Menoitios” . Originally, «λέγω» meant I collect, I gather the partial elements or categorisations into the unity which is indispensable for the manifestation of the existent. Crucially, to this original signification of «λόγος» corresponds the later interpretation of Philo of Alexandria: «When the λόγος of the being, being the bond of all things, as it is said, also holds together all the parts and hinders their being dissolved and separated» . The λόγος is identified with the presupposition of the original unity of the being, with the initial possibility of the manifestation of the singular character of the wholeness of the being, i.e. with that which the being is, when viewed as a “whole,” when viewed as an essence. As Plato states it: “One is the essence; one is the λόγος of the essence; one is the name” . The singularity of the λόγος of the essence preserves the singularly-specific character of the being: “this essence of which we give the λόγος of Being,” adds Plato  – which signifies that the λόγος of the being is identified with the essence of the being, that it is referred to that which the being principally is, as a given whole unity, i.e. it precedes the determination of the properties and notes (of those things which are predicated of the being).
-  Homer, Ἰλιάδος Ψ, 239.
-  Philo of Alexandria, De Fuga et Inventione, §112.
-  Plato, Νόμοι Ι, 895d 4–5.
-  Plato, Φαίδων, 78d 1.
The relation of the λόγος and essence of the being is analysed more systematically by Aristotle. In Aristotelian language, the partial elements of the unity of the being as a whole (matter, form and the “third of these”  – “that which is from both as a whole” ), as also the properties of the being as a collective whole (συνόλου) – as a composite wholeness of those things which are predicated of the being (“quality, quantity or each of the others of those things thusly predicated” ), give the possibility that the being “is spoken of in many ways” , such that “all are toward one principle”  – always with reference to the initial–original unity of the being, to the essence or nature of the being. When we say: the tree is woody (quality), the tree is tall (quantity), the tree is in the forest (place), the tree is ancient (time), the tree is fruit-bearing (operation) etc., we define in many ways this one being, which is the tree, but we presuppose the singular definition of its essence: this is a true – the initial unity of this being, this singularity of its essence; (“the essence of each thing is one”  – “and the one is nothing other than the being” ). The λόγος of the being precedes the categories, i.e. the properties of the being as a collective whole, and therefore it shows up in a presupposition of the understanding of the singularity of the being: “it is said that it is one … when the λόγος, of what it was to be (τὸ τί ἦν εἶναι), is one and the same” . And this singularity has the character of wholeness, it refers to all the partial existent units of the being, to as many as are “said to be one” – it is always a λόγος of the “whole” (“the λόγος is of the whole” ), it is “the λόγος regarding the thing” . The λόγος of the being refers to something, it is not a λόγος about something, it refers to the initial question: “what is this thing?” , i.e. in essence. “When speaking in so many ways of the being, it is manifest that of these the first is the what it is, which signifies the essence” . This identification of the λόγος with the possibility of manifestation of the essence of the being shows immediately the character of the λόγος as declaration. Not every λόγος is declarative , however the declaration – the presupposition that the being shine forth (ἀπο-φαίνεσθαι) in its essence – is always a λόγος.  The λόγος is declarative which is referential in essence (toward something) , the λόγος which says to us that something is or is not, that it exists or does not exist, that it manifests truth or is hidden. 
-  Aristotle, Μετὰ τὰ φυσικά Ζ, 1029a 2–4.
-  Aristotle, Μετὰ τὰ φυσικά Ζ, 1037a 6–7.
-  Aristotle, Μετὰ τὰ φυσικά Z, 1028a 12–13; cf. Δ 1017a 24–27: of the things predicated, some signify what it is (τί ἐστι), some which, some how much, some toward which (πρός τι), some doing or undergoing, some where, and some when”; and Ζ 1029b 24–25: “according to the other composites of other categories … with doing and how much and when and where and moving”; and Β 995b 35: “I say the composite whole, when something is predicated of matter.”
-  Aristotle, Μετὰ τὰ φυσικά Γ, 1003a 33–34: “The being is said in many ways, but toward one and one certain nature and not all with the same name.”
-  Aristotle, Μετὰ τὰ φυσικά Γ, 1003b 5–10: “The being is said in many ways but each is toward one principle; for the things are called beings because they are essences, because they are undergoings of the essence, because they are a way to essence or corruptions or privations or qualities or productions or generations of essence or that which is called relative to the essence, or negations of some of these or of essence.”
-  Aristotle, Μετὰ τὰ φυσικά Γ, 1003b 32.
-  Aristotle, Μετὰ τὰ φυσικά Γ, 1003b 31; cf. Δ 1016b 8–9: “the things that are firstly called one are the one essence”; and Ι 1053b25: the being and the one are said equally.”
-  Aristotle, Φυσικά 2, 185b 7–8.
-  Aristotle, Μετὰ τὰ φυσικά Ζ, 1035b 34–35.
-  Aristotle, Μετὰ τὰ φυσικά Ζ, 1034b 21.
-  Aristotle, Μετὰ τὰ φυσικά Ζ, 1028a 11–12.
-  Aristotle, Μετὰ τὰ φυσικά Ζ 1028a13–15.
-  Aristotle, Πρὸς Ἑρμηνείας 5, 17a 11–12: “For the λόγος of man, if there not added the is or the will be or the was or somesuch, so that there is a declarative λόγος.”
-  Aristotle, Περὶ Ἑρμηνείας 5, 17a 23–24: The simple declaration is the meaningful utterance concerning whether something exists or doesn’t exist.
-  Aristotle, Περὶ Ἑρμηνείας 5, 17a 15–16: “There is one declarative λόγος when either it shows one thing, or is one in connection.”
-  Aristotle, Περὶ Ἑρμνηείας 4, 17a 2–3: “Not every λόγος is declarative, but that one in which there exists being-true or being-false”; cf. John of Damascus, Διακετικά, 64 (Περὶ ἀποφάνσεως ἀποφάσεώς τε καὶ καταφάσεως); and Heidegger, Sein und Zeit, pp. 32f.
The operation of shining-forth (ἀπο-φαίνεσθαι), i.e. the function of the λόγος, that it manifests (it allows it to shine) the essence of the being, presupposes the collection (συλ-λογή) and assembly of the partial elements and categorisations of the whole and collectively-whole unity of the being, but also the exclusion of other elements and categorisations which do not belong to this unity: Thus we are led to the signification of the λόγος as definition, i.e. as limit of the distinguishing presuppositions of the singularity of the essence of each being. The λόγος, that which is declarative of the essence, limits, i.e. circum-scribes and separates, the elements which “signify” the uniqueness and singularity of the essence, expands and differentiates these elements from other “significant” elements of other essences. This definition refers to the singular character of the essence (“one is the λόγος of which we say to be a definition” ), presupposing the differences which display the singular uniqueness of the essence: “it is manifest that the definition is the λόγος of the differences” . And this singularity always has the character of wholeness, whether it refers to the uniqueness of the existing unity of the being (“this particular man or this particular horse” – first essence), or to all the partial existing units of the being, to “those things said to be one” (second essence) . Consequently, the λόγος as definition corresponds not only to the “meaning” of the singular wholeness of the essence, but also tot he manifestation of the mode of the assembly of the particular “parts” or distinguishing differences, which display the singular wholeness of the essence – the λόγος corresponds to the way or to the how of the existence of the essences. Inasmuch as, then, the beings are manifested with the λόγος, they are manifested according to the λόγος. The mode of their manifestation is defined by the declaratory λόγος of their essence, it is a rational mode, which refers to a harmonious and “orderly” («κατὰ τάξιν»: explanatory harmony and order) assembly of distinguishing differences and of partial “parts”, displaying the singularity of the whole essence – that which the being is: “every order is a λόγος” , “the for-the-sake-of-which is in the λόγος” . Thus we arrive at the significance of the λόγος as rational, of organic and explanatory series and order.
-  Aristotle, Μετὰ τὰ φυσικά Ζ 12, 1037b 11–12.
-  Aristotle, Μετὰ τὰ φυσικά Ζ 12, 1038a 8–9.
-  Cf. Κατηγορίαι 5, 2a 11–16 and Μετὰ τὰ φυσικά Ζ 13, 1038b 9–16.
-  Aristotle, Φυσικά Θ 1, 252a 13–14.
-  Aristotle, Φυσικά Β 9, 200a 14–15.
But the mode with which the the essence is, the singular wholeness and uniqueness of the essence, constitutes the species, its dissimilar form. Consequently the definition, as declaratory λόγος (i.e. λόγος which manifests the singular and unique character of the essence), refers to the species, it is a specifying λόγος: “for the definition is of the whole and of the species” . And the distinguishing difference, which displays the singular uniqueness of the essence, is a specifying difference: “the λόγος is from the differences of the species”  – “every specifying difference with the genus makes the species” . But the species can only “be signified”, i.e. be connected with the experience of its uniqueness, and therefore the λόγος as definition is a “sign” of the uniqueness of the essence: “the λόγος, of which the name is a sign, comes to be a definition” . The same name, as vicar vicar expression, does not have any significance when it is not a “sign”, i.e. symbol – when it does not throw-together (συμ-βάλλει, put together, unify) the partial experience of the species which each of us has separately, in order that it “signify” the being, i.e. to define it: “By nature, nothing is a name, but only when it becomes a symbol” . The signified species names the things: “the species puts names on the individuals familial to it” . The λόγος, consequently, as much as it is declarative, as much as it is rational, is identified with the possibility of manifestation of the essence only when it functions signifyingly and symbolically, i.e. only when it presupposes the experience of the form and refers to this experience. Here we could posit that the experience of the form presupposes and manifests the pre-cognitive relation of man with the “personal” uniqueness and unlikeness of beings, and consequently the λόγος, as declaration and rational, presupposes and manifests the personal relation of man with the beings, since the relation is the necessary and sufficient presupposition of the experience of the species, which the λόγος “signifies.”
-  Aristotle, Μετὰ τὰ φυσικά Ζ 11, 1036a 28–29.
-  Aristotle, Μετὰ τὰ φυσικά Η 2, 1043a 19–20.
-  Aristotle, Τοπικά Ζ 6, 143b 7–8.
-  Aristotle, Μετὰ τὰ φυσικά Γ 7, 1012a 23–24.
-  Aristotle, Περὶ Ἑρμηνείας 2, 16α 27-28.
-  Aristotle, Περὶ φυτῶν Α 1, 816a 14.
Source: Christos Giannaras, Πρόσωπο καὶ ἔρως, 4th edn. (Athens: Δόμος, 1987), §56.