COMMUNICATIONS RETINAL CYSTS ANDRETINOSCHISIS* BY C. G. KEITH DepartmentofPathology, Institute ofOphthalmology, University ofLondon SINCE the term retinoschisis came into commonophthalmological parlance, it has oftenbeenusedas thoughthe conditionwereadefinite entity, differing fromretinal cysts bythe process byWhichit arose.
The definition of imperative is something that has authority or is absolutely necessary. 1  An example of imperative is the power that a government has over its people.  An example of imperative is the decision to give a cesarean in a breach birth.
When something absolutely has to be done and cannot be put off, use the adjective imperative. Imperative is from Latin imperare to command, and its original use was for a verb form expressing a command: Do it! is an imperative sentence. It's still used that way, but it's more commonly applied to something so pressing it cannot be put off: Hiring new workers has become imperative..