zai

Zai is the pinyin transliteration for the Mandarin Chinese character 在. It is commonly written as 在 and pronounced zài in standard Mandarin. The core meanings are “at, in, on” and “to exist,” and the word functions as a locative preposition as well as a marker of ongoing action in verb phrases.

Locative use is the most frequent. It appears before a location phrase to indicate where something or someone is. Examples: 我在家 (I am at home); 他在学校门口等我 (He is waiting for me at the school gate); 书在桌子上 (The book is on the table). In many compounds it also contributes to meanings related to being present, present-tense location, or existence, such as 在场 (present, on the scene) and 在线 (online).

As a progressive aspect marker, 在 can signal ongoing action when placed before a verb. Examples: 我在吃饭 (I am eating); 他在看书 (He is reading). The more emphatic 现在进行时 form 正在 or 正在进行 can intensify this sense.

Time and other inline uses are common as well. It can indicate time frames such as 在三点见面 (meet at three o’clock) or 在暑假期间 (during the summer vacation). In some compounds, 在 appears as a prefix-like element, contributing to phrases describing state or location.

Notes: 在 and 再 (again) share the same pinyin zài in Mandarin, so context and characters distinguish them. In everyday Chinese, 在 ranks among the most frequent characters and appears in a wide range of expressions and idioms.