Versos alejandrinos are a type of poetic verse that consists of fourteen syllables divided into two hemistichs of seven syllables each, often marked by a pause (cesura) in the middle. This structure lends itself to both lyrical and narrative poetry, allowing for a grand and flowing expression of emotions and themes. In the context of 'A Julia de Burgos,' the use of versos alejandrinos emphasizes the strong, passionate voice of the speaker, reflecting themes of identity and self-assertion.