From earlier German Low German Kanickel, from a variant of Middle Low German kanīn, from Middle French connin (see Kaninchen). The form is probably based on Latin cunīculus. The -r-might have entered the word from the Brandenburg area, where non-rhotic and strongly rhotic Low German dialects neighboured. The word was probably pronounced with [äː], a sound close to the northern Brandenburg realisation of /ar/, which is [aː]. This led to a pronunciation with [ar] for some southern, rhotic speakers, which was still considered a random idiosyncrasy in 1903.
- “Karnickel” in Duden online