It is called hemistich to half of a verse . The term, which derives from Latin hemistichĭum (in turn originated in the Greek hēmistíchion), is usually used to refer to each fragment of a verse that is separated from others by a caesura .
This means that, beyond the allusion to a "half" (indicated by the Royal Spanish Academy in its dictionary ), hemistichs are not always two equal parts in which a verse is fragmented. It is possible that these parts are not equal, or that a verse has three or more hemistichs.
This concept is part of the metrics , which is defined as the sum of all the regularities of formal and systematic type that serve to characterize the prose Rhythmic and poetry versified. From a metric point of view, the study of writing is divided into three important parts: the poem, stanza and verse.
If we focus specifically on the Spanish metric, we have a verse that is composed of an invariable number of syllables and a certain distribution of accents , with a rhyme of optional type. In our language you can also find works with quantitative metrics, that is, the one that arises when forming verses concatenating syllables, which in other languages can have two or more durations; grecolatina is a clear example of quantitative metrics, since it was created based on the repetition of some sequences of long and short syllables, the so-called feet.
In the metrics , the hemistichs are taken as full verses . In the case of the Castilian metric, the verses of more than nine syllables have hemistichs. Therefore it can be stated that a Alexandrian verse , which consists of fourteen metric syllables, consists of two hemistichs, each of seven syllables.
Similarly, a dodecasyllable verse which has a total of twelve syllables is formed with two hemistichs of six syllables. The hemistichs of the Alexandrian verbs and the dodecasyllabic verses are separated by the mentioned caesurae, which are pauses or cuts .
While we can define the word caesura in a simple sentence, it is one of the fundamental concepts of poetry . Without this pause or this space inside each verse, oral reading and understanding of the works would be affected. From an academic point of view, in the verses that contain more than eleven syllables we cannot fail to include at least one caesura. Anyway, we must not forget that poetry arose before all these technical concepts, which serve to understand it and, depending on each author, take it to new horizons but do not constitute an infallible recipe for creating art.
Let's take the example of the poem “Al-Hamar's career” of the Spanish writer Jose Zorrilla , born in 1817 and died in 1893 . In this composition the following verse appears:
“Medrosas, pretending lost visions”
It is a dodecasyllable verse since it has twelve syllables: me-dro-sas fin-gien-do vi-sio-nes lost-di-das. On the other hand, this verse shows a caesura which divides it in two: fearful, faking // lost visions. Therefore the verse “Medrosas, pretending lost visions” It has two hemistichs: “Medrosas, pretending” and "Lost visions".
On the other hand we have the concept of heterostychium , which also belongs to the scope of the metric and is defined as each part unequal into which a major art verse is divided once the caesura enters into action. For example, if we take a case-based verse that is divided into a part of six and another of four syllables, we can say that each of them is a heterostich. The difference between this and hemistich is very simple: it would be two hemistichs if both parties had the same number of syllables.