The term siphon is used for a number of biological structures, either because flowing liquids are involved or because the object is shaped like a siphon. In these structures, the physical phenomenon known as the siphon effect is not present.

• Hyponome or siphon is an organ of many aquatic mollusks.
• Oral siphon of Urochordata
• Siphon (insect anatomy)
• Carotid siphon, a portion of the human internal carotid artery running through the cavernous sinus, called so because of its shape.
• siphon gourd