- [countable]
something, such as a piece of information, that is necessary for somebody to be able to understand a problem or in order to make something complete （理解问题或使事物完整的）必要的环节，不可缺少的一环 He may be able to provide us with the missing link that can help us solve the mystery. 他也许能够为我们提供缺少的链接，从而帮助我们解决这个谜团。
- the missing link[singular]
an animal similar to humans that was once thought to exist at the time that apes were developing into humans 缺环（推想中从类人猿发展到人类之间的过渡动物）