Noun

• S: (n) pore (any tiny hole admitting passage of a liquid (fluid or gas))
• S: (n) pore (any small opening in the skin or outer surface of an animal)
• S: (n) stoma, stomate, pore (a minute epidermal pore in a leaf or stem through which gases and water vapor can pass)

Verb

• S: (v) concentrate, focus, center, centre, pore, rivet (direct one's attention on something) "Please focus on your studies and not on your hobbies"