Writers can use different other common word having the same meaning with the unfamiliar word or can provide definition in an easy and simple way to make it understand to the readers.
Explanation:
Unfamiliar concepts or unfamiliar terms are difficult to understand by the people as they are aware of it or its meaning. People can relate only to what they know and what they have learned. So writers can compare and contrast the unfamiliar term or concept with some familiar thing so that the people can understand them.
Besides the writers can also use synonym words for the unfamiliar word so it help the readers. The readers can also make an effort by defining the term and explaining the concept in the simplest possible way so that ordinary man can understand in a layman language. Readers can also use extended definition, that will help a lot.