Bottom cowrie radical - the indexing radical, pictograph of a cowrie shell. In ancient China cowries were money, so
贝 marks
贯 as a financial unit: a string of cash (one
贯 = 1000 coins on a cord). Anchors it in the money family with
财,
货,
购. From threading coins came the abstract run through, be consistent (
一贯,
贯彻).