pore
     n 1: any tiny hole admitting passage of a liquid (fluid or gas)
     2: any small opening in the skin or outer surface of an animal
     3: a minute epidermal pore in a leaf or stem through which
        gases and water vapor can pass [syn: {stoma}, {stomate}]
     v : direct one's attention on something; "Please focus on your
         studies and not on your hobbies" [syn: {concentrate}, {focus},
          {center}, {centre}, {rivet}]
Source: WordNet® 2.0