Pore

• Sweat pore, an anatomical structure of the skin of humans (and other mammals) used for secretion of sweat
• Canal pore, an anatomical structure that is part of the lateral line sense system of some aquatic organisms
• Gonopore
  Gonopore
  
  A gonopore is a genital pore in some invertebrates and especially some insects.For insects, it is the opening of the genital duct. More specifically, in the unmodified female it is the opening of the common oviduct, and in the male, it is the opening of the ejaculatory duct....
  , a genital pore present in some invertebrates, particularly insects
• An opening across both inner and outer bacterial membranes, a part of many Gram-negative bacterial secretion systems
  Secretion
  
  Secretion is the process of, elaborating and releasing Chemical compound from a cell , or a secreted chemical substance or amount of substance. In contrast to excretion, the substance may have a certain function, rather than being a waste product....
  
• One of the openings communicating with the skin surface at the terminus of lactiferous duct
  Lactiferous duct
  
  Lactiferous ducts lead from the lobules of the mammary gland to the tip of the nipple. They are also referred to as galactophores, galactophorous ducts, mammary ducts, mamillary ducts and milk ducts....
  s in milk-producing mammals

• Stoma
  Stoma
  
  In botany, a stoma is a pore, found in the leaf and stem epidermis that is used forgas exchange. The pore is formed by a pair of specialized parenchyma cells known as guard cells which are responsible for regulating the size of the opening....
  , a small opening on a plant leaf used for gas exchange
• An anatomical feature of the anther in some plant species, the opening through which pollen is released
• A characteristic surface feature of porate pollen

• Nuclear pore
  Nuclear pore
  
  Nuclear pores are large protein complexes that cross the nuclear envelope, which is the double Endomembrane system surrounding the eukaryote cell cell nucleus....
  , a large protein complex that penetrates the nuclear envelope in eukaryotic cells
• Ion channel pore; The ion-selective opening in the membrane of a eukaryotic cell formed by members of the ion channel
  Ion channel
  
  Ion channels are pore-forming proteins that help establish and control the small voltage gradient across the plasma membrane of all living cell s by allowing the flow of ions down their electrochemical gradient....
   family of proteins
• A water-selective opening (water channel) in the membrane of a eukaryotic cell formed by assemblies of the protein aquaporin
  Aquaporin
  
  Aquaporins are proteins embedded in the cell membrane that regulate the flow of water. They are "the plumbing system for cells."Aquaporins are integral membrane proteins from a larger protein family of major intrinsic proteins that form pores in the cell membrane of cell s....
  

• One of many small openings in a solid substance of any kind that contribute to the substance's porosity
  Porosity
  
  Porosity is a measure of the void spaces in a material, and is measured as a fraction, between 0?1, or as a percentage between 0?100%. The term is used in multiple fields including ceramics, metallurgy, materials, manufacturing, earth sciences and construction....
   (typical usage in earth sciences, materials science and construction)
• A small defect in the crystal structure that may arise during sintering
  Sintering
  
  Sintering is a method for making objects from Powder , by heating the material below its melting point until its particles adhesion to each other....
   to form solids from powders, including ceramics

See also

• Aperture
  Aperture
  
  In optics, an aperture is a hole or an opening through which light is admitted. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of ray that come to a focus in the ....