ATLAS OF LANGUAGE

AT-NAV-G03-029 · ATLAS 259

Isogram

An isogram is a text or expression in which units from a defined character set do not repeat.

Part of the subject path Poetics, Narrative and Representation

Why is this entry in the Atlas?

E · Selected case R3 · Justified illustrative case

Isogram offers nonrepetition as a concrete writing constraint alongside other letter-based rules. Character level and normalisation determine whether the constraint is actually satisfied.

Colours and admission grounds

The rectangular label identifies the entry function: F – linguistic figure or procedure; A – analytical concept; G – foundational concept; E – selected concrete case. The rounded badge indicates the admission ground: R1 – distinctive contribution; R2 – necessary foundation; R3 – justified illustrative case. This editorial rationale explains the current selection rather than claiming an undocumented original selection history.

Explanation

Isogram is used here in the broader wordplay sense of an expression in which every occurring letter appears equally often. The frequency must be specified. When each occurs once, the result matches the source entry's heterogram definition; narrower uses restrict isogram to that case. Counting also requires prior conventions: are case differences ignored, spaces removed or accented letters normalised? A fixed procedure turns an impression of unusual letter distribution into a testable property. This entry does not claim uniform terminology across wordplay traditions.

Movement of thought

1. Specify the expression. 2. State normalisation conventions. 3. Count each letter. 4. Compare the frequencies. 5. Classify the expression with its order n stated.

Scientific use case

A small program can reproduce the counts, provided the normalisation rules are preserved with the result.

Example

Normalising case turns “Mama” into mama: m and a each occur twice. Under the broader convention adopted here, it is a second-order isogram.

Counterexample

Mamma contains three instances of m and two of a, so it fails the equal-frequency rule.

Distinction

Distinguish the broader definition, first-order isograms and the source entry's heterogram convention.

Effect on thought and perception

The constraint reveals linguistic material as a discrete arrangement.

Resonance

Alongside meaning, words display another order made of recurrence and distribution.

Provenance

Parallel source review reconciled 2026-10-07; human specialist review not claimed.

Cite this entry

Reich, Michael (Hrsg./ed.): „Isogram“. Atlas der Sprache, AT-NAV-G03-029. ATLAS 259, data model 1.6.0. https://atlasoflanguage.com/concept/AT-NAV-G03-029

https://atlasoflanguage.com/concept/AT-NAV-G03-029

The address remains stable; editorial content may evolve. Editorial reading state: 2026-10-15. Include your access date for precise references.