What does mora mean?
In phonology and prosody, a mora is a unit of syllable weight or duration, roughly equivalent to a short vowel or consonant. It is not identical to a syllable: a syllable may contain one or several morae, depending on its structure and the linguistic framework being used. This distinction is especially important in Japanese, where a syllable such as the word ai can contain two morae. In poetry and metrical analysis, morae serve as units of rhythmic time, with long syllables conventionally divided into two such units. The term also has a historical use for a brief unit of time in measurement. Although uncommon in everyday English, it provides linguists and students of prosody with a precise way to describe how syllables acquire weight and duration. The word comes from Latin mora, meaning “delay” or “a period of time,” and entered English through the study of meter and phonology.
nounIn phonology and prosody, a mora is a unit of syllable weight or duration, corresponding roughly to a short vowel or consonant; a syllable may contain more than one mora. In metrical analysis, it is a rhythmic unit corresponding to a short syllable or to part of a long syllable.
- A unit of syllable weight or duration in phonology, roughly corresponding to a short vowel or consonant and capable of combining with other units within a syllable.
- A unit of metrical time or rhythm in poetry and prosody, corresponding to a short syllable or to one part of a long syllable.
- Historically, a unit of time in rhythmic or musical measurement, conventionally equal to the duration of a short syllable.
"In the analysis of English rhythm, the vowel in hit contributes one mora."
"In Japanese, the word ai contains two morae even though it is written as one syllable."
"When reading Sanskrit poetry, the teacher asked the students to count the morae in each line."
Moras is common in general linguistic use, while morae is frequently used in discussions of verse and metrical structure.
"The poem has a varying number of morae in each line."
One syllable can contain several morae, so a mora is not the same thing as a syllable.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does mora come from?
The word comes from Latin mora, a noun meaning “delay” or “a period of time.” Latin morari, “to delay, linger, or wait,” is the source of the same family, including moratory and demur. The metrical sense developed because a mora became a unit of time in verse and later a basic unit of syllable weight in phonology.
Related word forms
How mora is actually used
This is primarily technical vocabulary used in phonology, prosody, poetry, and comparative linguistics. It is not normally used in everyday English, although the Japanese distinction between mora and syllable is often explained in English-language linguistics materials.