Onikos describes the millstone placed around a person's neck in warnings about causing little ones to stumble.

In both attested warnings, onikos qualifies the millstone placed or hung around a person's neck before being cast into the sea.

1. Millstone in a warning of severe consequence · dominant

   The nominative singular masculine form occurs with the millstone in warnings about causing little ones to stumble. In Mark 9:42 the APB renders a millstone surrounding the offender's neck before he is thrown into the sea; in Matthew 18:6 it renders a millstone hung around his neck before he is drowned.

   Mark 9:42Matthew 18:6

In the Anselm Project Bible: Across both verses, the APB presents the term within “a huge millstone,”. It describes the millstone as surrounding the neck in Mark 9:42 and being hung around it in Matthew 18:6.