The key is the symbol of access and answers. Finding one is traditionally read as a solution coming within reach; losing one, as feeling shut out. A key that does not fit the lock points to the right effort in the wrong place, or an approach that needs changing. Being handed a key by someone is read as trust, responsibility or a new role being offered. A ring of many keys suggests several options at once, and a broken key a plan that has stalled. Dream books often ask which door in your life the key belongs to.
Has this come up in your dreams before? What was going on in your life then?
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.