Exploring the Meaning of Mekos in Greek

μῆκος expresses “length” in Scripture, appearing where dimensions are set side by side for comparison and comprehension. In its New Testament uses, it serves both reflective description and precise measurement.

Root and Related Words

μῆκος is connected (per Strong’s) with the adjective

megas (μέγας), “great” (Strong’s G3173)

in a relationship of derivation.

Occurrences

Ephesians 3:18 — may be strengthened to comprehend with all the saints what is the width and length and height and depth,

Here μῆκος stands among four named dimensions: “width and length and height and depth.” The wording places “length” in a coordinated list, as one axis of a full dimensional portrayal. The phrase “may be strengthened to comprehend” frames these dimensions as an object of shared grasp (“with all the saints”), so “length” contributes to a picture of something that calls for more than a single line of thought: it is something to be comprehended in breadth and extension, in vertical reach and in depth. Within that rhetorical arrangement, μῆκος functions as a necessary component for a complete description—without it, the set of dimensions would be incomplete, and the movement from “width” to “height” would skip over the ordinary way extension is spoken of in space. “Length” thus participates in the verse’s piling up of dimensional terms to express the scale of what is to be comprehended, while keeping the language concrete and measurable in feel even as it is used for contemplation.

Revelation 21:16 — The city is square, and its length is as great as its width. He measured the city with the reed, twelve thousand twelve stadia. Its length, width, and height are equal.

In this description of the city, μῆκος is first used for a comparison: “its length is as great as its width.” “Square” sets the expectation of equal sides; the clause then states the equality explicitly by linking “length” and “width.” μῆκος here is not merely a casual descriptor but a defining property of shape, helping the reader picture a city whose outline can be characterized by equal horizontal dimensions.

The verse then adds measurement: “He measured the city with the reed, twelve thousand twelve stadia.” Against that act of measuring, “length” is one of the values that can be taken and stated. The final sentence extends the equality beyond the first comparison: “Its length, width, and height are equal.” μῆκος is repeated, now within a triad, and placed alongside “height.” The effect is to describe not only a square plan but an equality of dimensions in multiple directions. In this setting μῆκος anchors the statement in a measurable axis, enabling the portrayal of the city’s proportion through explicit equivalence of dimensions.

Sense and Usage

Across these passages, μῆκος serves as the term for one dimension among others when something is portrayed through its measurable aspects. In Ephesians 3:18, “length” is paired with three other dimensional terms, and the emphasis falls on comprehension: the vocabulary of dimension is recruited to express the scale and fullness of what is to be grasped. The word’s contribution is to give that portrayal extension—an imagined reach from one end to another—while remaining part of a balanced set of dimensions rather than standing alone.

In Revelation 21:16, μῆκος is used in a more literal and architectonic frame: shape (“square”), comparison (“as great as”), measurement (“measured…with the reed”), and proportion (“are equal”). “Length” here helps establish the city’s geometry and the equality of its dimensions. The term works naturally with language of measuring and with statements of equality, showing how “length” can be both a property compared to another property and a dimension included within a full specification of form.

Taken together, the uses show μῆκος as a word that fits readily into lists of dimensions and into statements that relate one dimension to another. Whether the focus is on being “strengthened to comprehend” or on a city whose dimensions are declared and measured, μῆκος carries the straightforward idea of extension and supports descriptions that depend on spatial comparison and completeness.

Imagery

Both contexts draw on the mental picture of dimensions laid out together. Ephesians 3:18 evokes a kind of fourfold spatial framing—width, length, height, depth—inviting the hearer to think of something with full extension in every direction. Revelation 21:16 fixes that dimensional language to a visible scene: a city whose “length” matches its “width,” measured with a reed, and described as having equal dimensions, so that the reader is led to imagine an ordered, fully proportioned structure.

Sources: Lexical data from Strong’s Exhaustive Concordance and the Translators Brief Lexicon of Extended Strongs for Greek (STEPBible, CC BY). Occurrence data from the Translators Amalgamated Greek New Testament (STEPBible, CC BY). Scripture quotations from the World English Bible (public domain).