Coherence refers to how meanings and sequences of ideas relate to each other in a logical way, such as from general to specific. Cohesion refers to the grammatical and lexical links within a text that give it meaning. There are various devices that can achieve cohesion, including reference, ellipsis, substitution, lexical repetition, and conjunctions. Together, coherence and cohesion work to create a unified text where the relationships between ideas are clear and the meaning flows smoothly from one sentence or paragraph to the next.