Diachronic approaches give us a history, like a motion picture documentary. They focus on how things change over time . In contrast, a synchronic approach gives us a snapshot of a particular system at a particular moment in time, like a snapshot. For example we might note how a word is distinguished from other words at the moment. Synchronic approaches focus on how a given system is at a given moment and how each part fits into the system.
Structuralism relies on a synchronic approach.
Discourse Michel Foucault uses this term for an authoritative way of describing. Discourses are propagated by specific institutions and divide up the world in specific ways. For example, we can talk of medical, legal, and psychological discourses. Literary criticism is also a discourse, as is the terminology associated with grading. Essentialism usually comes up in debates about personal identity .