vão

Vào is a common Vietnamese word that functions as both a verb meaning to enter and as a preposition indicating movement into or within a space, and it can also mark a point in time. It is a native item of core vocabulary and appears in a wide range of constructions in spoken and written Vietnamese.

As a verb, vào takes a target such as a place, room, or state: Tôi vào nhà (I go into the house), Cô ấy vào lớp (She attends class / goes to class), and Anh ấy vào nghề báo (He enters the journalism profession). It is also used in phrases meaning to begin or undertake something, for example vào làm or vào nghề (to start work or to join a trade).

As a preposition, vào precedes a noun phrase to indicate movement into a place, or marks a point in time: vào nhà, vào cửa, vào lúc 8 giờ, vào ngày 1 tháng 5, vào năm 1990. In these usages it can express location, direction, or temporal reference depending on the surrounding context.

Usage notes and variations: In more formal or literary contexts, vào trong can be used to emphasize entering into the interior of a space. In everyday speech, vào often stands alone before a time or place word. Etymology: vào is a native Vietnamese word with no standard Sino-Vietnamese origin. It is widely used across dialects and forms a core part of many common collocations, including động từ (verbs) that express movement or transition and prepositional phrases that anchor nouns in space or time. See also related constructions such as đi vào (to go into) and trong (inside) for contrast.