The spelling of the word "in dern" may seem confusing, but it can be easily explained using IPA phonetic transcription. The first syllable "in" is pronounced as /ɪn/, while the second syllable "dern" is pronounced as /dɜːn/. The "d" is pronounced as /d/ and the "ern" is pronounced like the word "earn" but with a stronger "r" sound. Overall, the correct spelling and pronunciation of "in dern" can be easily mastered with a bit of practice.
There doesn't seem to be a widely recognized term or concept called "in dern". It is possible that you meant to type a different word or phrase. If you can provide more context or clarify your request, I would be happy to assist you further.