1- An umbrella is a shelter and a sanctuary and it is this symbolism that comes across in dreams. Often in a work situation we need to work under someone’s teaching, and this feeling of safety can be recognised in dreams.
2- As we mature we need to develop certain coping skills. In dreams these can be seen as a protective covering, hence the image of the umbrella.
3- As a sunshade conferred status and power, so does the umbrella.... Ten Thousand Dream Dictionary