Metaphor originated from the Greek word, metaphor which simply means to transfer. Analogy on the other hand came from the Greek word, analogia which means proportion. Given these etymologies, metaphor is a figure of speech that actually transfers the meaning of one thing directly on another unit.
Medicines that are taken âas neededâ are known as âPRNâ medicines. âPRNâ is a Latin term that stands for âpro re nata,â which means âas the thing is needed.â. Itâs important to know the difference between daily and âas neededâ medicines.hese instructions should include the following information: 1  How much medicine you can take in a set period of time. 2  When to take your PRN medication. 3  When to take scheduled and PRN medications for a single health problem.
Definition. PRN is an abbreviation that comes from the Latin term pro re nata.. Its actual translation to English is for the thing born, but its common medical meaning is as needed.. It used to identify a medication that can be taken as the patient needs it rather than on a fixed schedule.he most common types of PRN medications are those that treat occasional conditions. These include drugs to control pain, sleeping pills, anticongestants, cough medicine and medications that treat occasional stomach distress.