What does coherence mean?
Coherence refers to the state or quality of being logically consistent, well-organized, and connected as a whole. When an argument, a piece of writing, or a system has coherence, all of its parts fit together smoothly so that the whole makes sense. The word also carries a physical meaning: in science, coherence describes the property of waves or particles remaining in a fixed, orderly relationship with one another, as in laser light. Coherence is generally valued positively — a coherent plan inspires confidence, while a lack of coherence suggests confusion or carelessness. It appears frequently in academic, philosophical, and technical contexts, though it is useful wherever clarity of structure matters. Closely related to cohesion but distinct from it, coherence emphasizes internal logic and unity rather than mere sticking together. Its opposite, incoherence, signals disorder or contradiction.
nounThe quality of being logically or aesthetically consistent, unified, and connected as a whole; the property of holding together in a coherent way.
- Logical consistency and clarity in thought, speech, or writing.
- Physical or structural unity — the quality of holding together as a whole.
"The essay's coherence made its complex argument easy to follow."
"Her argument lacked coherence because each paragraph contradicted the last."
"Physicists study the coherence of light waves to understand how lasers work."
Rarely pluralized; typically used only when referring to multiple instances of the concept in technical contexts, e.g., different states of wave coherence.
"The paper examined several distinct coherences among the observed signals."
In physics, coherence is literally why lasers work — every photon marching in step with the others — while in writing it is why an essay persuades rather than merely rambles.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of coherence
Coherence comes from the Latin verb cohaerere, meaning 'to stick together', formed from co- ('together') plus haerere ('to adhere'). It entered English in the early modern period, around the sixteenth century, via French or directly from Latin. It shares this root with adherent words such as adhesion and inherent, all descended from haerere.
Related word forms
How coherence is actually used
A somewhat formal word common in academic, scientific, and critical writing. In everyday speech 'made sense' often substitutes for it.
Easily confused with coherence
Cohesion refers to the physical act of parts sticking together, while coherence refers to logical or conceptual consistency and unity.