A sundress is traditionally read as joy, summer freedom and an easy openness to the world. It often marks a mood of letting warmth in after a colder stretch.
Where in your waking life have you met something like this lately?
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.