• 株主かぶぬし — shareholder
• 株式かぶしき — stock (of a company)
• 親株おやかぶ — parent stock / original plant
• 株価かぶか — stock price
• 古株ふるかぶ — old-timer / veteran

株 combines the tree radical 木 with 朱 (シュ, “vermilion”). Originally referring to a stump or root, it later symbolized shares or authority that branch out from a central source. Today it’s essential in business contexts (株式, 株主) while still keeping its older meaning of tree stumps or roots.