Source: The Great Interpretation of Dreams (Ibn Sirin)
An umbrella in a dream is a ruler or a man of high status to whom people resort. Taking shelter under it indicates gaining protection and benefit.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
An umbrella indicates protection from harm. For the traveler, it is a return, and for the fearful, it is security.
Source: Signs in the Science of Expressions (Ibn Shaheen)
An umbrella is interpreted as a noble man. Whoever sees himself taking shelter under it will attain goodness.