The umbilical cord stands for dependence and the first bond with a mother. Cutting it is read as a step towards independence; a cord still attached as ties that hold on.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.