The phrase refers to scheduled social engagements, typically romantic in nature, planned to occur in outdoor settings characteristic of vast, open landscapes. An example would be a picnic at sunset in a wide-open field, or an evening spent stargazing away from city lights.
Such engagements often foster a sense of connection with nature and can provide a unique backdrop for creating memorable experiences. Historically, cultures have valued outdoor settings for socialization and relationship building, recognizing the tranquil and inspiring effects of natural environments.