An organ is a collection of tissues joined in a structural unit to serve a common function.[1] In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a function. Tissues of different types combine to form an organ which has a specific function.
你貼嗰段話『An organ is a collection of tissues joined in a structural unit to serve a common function』,OK,呢個定義我完全同意。問題係,單一嘅骨頭只係硬組織,佢的確係由多種組織組成,但佢唔具備一個『獨立』嘅功能。你引用嘅資料仲講得好清楚:『In the hierarchy of life, an organ lies between tissue and an organ system.』意思係器官喺組織同器官系統之間,係一個獨立單位,而唔係單一嘅組織。
另外,牙齒嘅主要功能係咬合同咀嚼,佢係消化系統嘅一部分,唔可以獨立完成消化。即使佢有神經同血管,呢啲只係輔助組織,唔代表佢可以稱為獨立嘅器官。你可以睇返Wikipedia 上面嘅「List of organs of the human body」嗰篇文章,牙齒的確被列為消化系統嘅一部分,但佢唔係獨立嘅器官。