Any article that penetrates or pierces another, such as a knife or laser beam, signifies that the normal boundaries and limitations by which we live are illusions when viewed from a spiritual perspective.
Psychological / emotional perspective: In today’s world people tend to view penetration from a purely sexual viewpoint. In dreams it usually signifies getting to the heart of a matter. Any pointed object represents male sexuality but can also be interpreted in the above manner.
Material aspects: Inherent in the idea of penetration is a piercing of defences and this meaning is one which arises frequently in dreams. When we are feeling particularly vulnerable or at risk, dreams such as of castle walls being penetrated can occur.
Gives gender - specific: Myths and fairy tales often give information that resonates in dreams. Women and men exploring their sexuality or their need for partnership can have dreams that highlight both penetration of a sexual nature and that of personal space. Consulting the entries for castle, dagger, knife and sex / sexual images might help with further clarification.