Spiritual Meaning:
Since a knob of any sort is usually used to gain access to something, spiritually it can suggest changes occurring in the way we approach our unconscious self.

Psychological / Emotional Perspective:
To be dreaming of a knob such as a doorknob can indicate some kind of turning point in our life. A noticeable contrast between the door and the knob can present the dreamer with certain insights. For instance, a very plain knob on an ornate door may indicate that the process of moving forward from a situation is very easy. The knob coming off in our hands suggests a missed opportunity. We may need to turn or change issues or conditions.

Everyday Material Aspects:
When we are turning a knob we need to decide whether we are turning it clockwise or anti-clockwise. Clockwise will signify a positive move, anti - clockwise perhaps an initially more difficult one, but one which will ultimately present further opportunities.

Gender / Specific Meanings:
Since many people still have difficulty in calling ‘private parts’by their correct name, a knob appearing in a dream can represent the penis or, if the dreamer is a man, his masculinity.

You might also like to consult the individual entry for Door and also Door in Buildings.