A synchronic approach (from Ancient Greek: συν- "together" and χρόνος "time") considers a language at a moment in time without taking its history into account. Synchronic linguistics aims at describing a language at a specific point of time, often the present.
A diachronic (from δια- "through" and χρόνος "time") approach, as in historical linguistics, considers the development and evolution of a language through history.