The article attempts to highlight two aspects of the sonnet's semiotic mechanisms from which the dynamics and openness of this form emerge. Firstly, in the production of meaning from the synchronic aspect and secondly, diachronically viewing the sonnet as a process that has a tendency towards the constant opening of this canonical form. So the boundaries of the sonnet are not only closing the form but also lead every single sonnet towards opening. The paper aims to indicate through the history of the sonnet and some exemplary cases the essential characteristics of this canonical form of poetry, suggesting that inner openness and flexibility is in the very core of the sonnet. It is suggested that experimenting with the form is very essential to the sonnet; stretching the limits of the sonnet helps to mark its boundaries and at the same time these dynamics stand for its longevity. This is the reason why the sonnet has remained a challenge over centuries in so many cultures.