Definition
To use something; to make use of a tool, method, or resource.
Example
你可以用手机查地图。
Show translation
You can use your phone to check the map.
Etymology
Oracle-bone and bronze inscriptions show 用 as a pictograph of a bucket or vessel being put to practical purpose. By the time of Classical Chinese it had fully generalized to mean "to employ, to use, to apply." It also functions as a noun (有用 yǒuyòng, "useful") and appears in countless compounds: 使用 shǐyòng (to use/operate), 费用 fèiyòng (expense), 应用 yìngyòng (application/app).
Cultural note
用 is one of the most versatile words in Mandarin. A very common pattern is 用 + TOOL/METHOD + VERB, e.g. 用筷子吃饭 (use chopsticks to eat) or 用中文说 (say it in Chinese). Be careful not to confuse it with 花 (huā), which specifically means "to spend" time or money — a nuance English speakers sometimes miss.