Cohesion is the grammatical and lexical linking within a text or sentence that holds a text together and gives it meaning. It is related to the broader concept of coherence.
There are two main types of cohesion:
A cohesive text is created in many different ways. In Cohesion in English, M.A.K. Halliday and Ruqaiya Hasan identify five general categories of cohesive devices that create coherence in texts: reference, ellipsis, substitution, lexical cohesion and conjunction.