when a certain word which is to be defined crops up in its own definition, we call it a circular definition. the point of defining a term is to explain its meaning; this obviously cannot be achieved if you need already to understand the meaning of the term in order to understand the definition. _________________________. for example, to define “stress” as “the physiological and psychological responses to stressful situations” would be to give a circular definition. this is because stressful situations are presumably only recognizable from the fact that they tend to produce stress: but the meaning of “stress” is the very thing which someone requesting the definition is seeking to understand, and so should not be presupposed in the definition. to define “philosophy” as “the activity carried out by philosophers” would be another example of a circular definition. [3점]
① words out of circulation lose their meanings
② words should be defined depending on context
③ circular definitions, then, miss the point of definition
④ to explain words effectively, make use of examples
⑤ evolution of languages, however, occurs along with time

답이 3번인 건 알겠는데 1번은 어떤의미를 나타내는건가요