Mathematics A set of elements or points satisfying specified geometric postulates: non-Euclidean space. The infinite extension of the three-dimensional region in which all matter exists. The expanse in which the solar system, stars, and galaxies exist; the universe. The region of this expanse beyond Earth's atmosphere. An extent or expanse of a surface or three-dimensional area: Water covered a large space at the end of the valley. A blank or empty area: the spaces between words. An area provided for a particular purpose: a parking space. Reserved or available accommodation on a public transportation vehicle. A period or interval of time. A little while: Let's rest for a space. Sufficient freedom from external pressure to develop or explore one's needs, interests, and individuality: "The need for personal space inevitably asserts itself\u201d ( Maggie Scarf). Music One of the intervals between the lines of a staff. Printing One of the blank pieces of type or other means used for separating words or characters. One of the intervals during the telegraphic transmission of a message when the key is open or not in contact. Blank sections in printed material or broadcast time available for use by advertisers. To organize or arrange with spaces between. To separate or keep apart. Slang To stupefy or disorient from or as if from a drug. Often used with out: The antihistamine spaces me out so I can't think clearly. Slang To be or become stupefied or disoriented. Often used with out: I was supposed to meet her, but I spaced out and forgot.