Core Meanings
"一体" can mean "one entity" or "whole", referring to things combined or unified. It is also used as an intensifier in questions to express strong curiosity or confusion, similar to "on earth" or "in the world" in English.
Usage in Sentences
As a noun or adjective, it describes unity or integration, e.g., "一体结构" (integrated structure). As an adverb in questions, it adds emphasis, e.g., "你一体想干什么？" (What on earth do you want to do?).
Common Collocations
Notes
Do not confuse "一体" with "整体" which also means whole but is more formal and abstract.