noun, plural: nuclear pores
Nuclear pores pertain to the numerous openings in the [nuclear envelope]]. They are octagonal in shape owing to the assembly of protein molecules called nucleoporins. The pore measures about 9 nm in diameter whereas the depth is about 200nm.
These openings allow the entry and exit of select biomolecules. For instance, ribonucleoproteins leave the nucleus whereas certain proteins (e.g. DNA polymerases), carbohydrates, lipids, and signaling molecules enter the nucleus through the nuclear pores.