In Korea, a noun+란(ran) is used when you want to define the noun.
Its definition is usually from the speaker's idea and has a sense of emotion.

사랑?--> (love?) : 사랑이란? --> [emotionally you are asking. (What is love?)]
If the last letter is a vowel, it should be +이란. In Korea, ng sound is defined as vowel. so 사랑(SARANG)+이란.is correct.