变化 (biànhuà) means 'change' or 'variation' and can be used as both a verb (intransitive) and a noun. Unlike 变 (biàn), which often means 'to become' followed by an adjective (e.g., 变红 'turn red'), 变化 emphasizes a natural or gradual process. It is also different from 改变 (gǎibiàn), which is transitive and implies a deliberate alteration.