he·li·o·space (ˈhē-lē-oˌ-spās), n. [neologism based on the ancient greek helios, mythological sun god, and outer space] 1. The volume populated with objects in orbit around our sun. 2. The space beyond earth's atmosphere and within the solar system. 3. All elements and systems that compose the volume influenced by the sun. -- SYN. "everything and everywhere under the sun".
