Meaning “15 syllables,” each verse is a single fifteen syllable line written in iambic heptameter. The form is also commonly referred to as “Political Verse” - indicating not political topics but the Greek root word of “polis” for people or civic poetry. As Topintzi and Versace note, the dekapentasyllavo “is the most important indigenous meter of the Modern Greek” poetic tradition, spanning centuries and genres - including folksongs and written poetry. The first eight syllables form the main theme of the poem. The seven syllables after the cesura either reinforce or complicate the main theme. The poems are often written in two-verse stanzas, with poems being as short as two lines and can be as long as desired, with some being thousands of lines long. 

Sources:

Topintzi, Nina & Versace, Stefano (2015) ‘A Linguistic Analysis of the Modern Greek Dekapentasyllavo Meter.’ Journal of Greek Linguistics, Vol 12, pgs 235-269.