Definition of double-spaced in English English dictionary
formatted so that there is a full blank line between each line of text; the style of formatting required by many entities inside business, academia, and publishing
(of type or print) having a blank line between lines of type; "manuscripts must be double-spaced
A typesetting specification (particularly for typewriters,) indicating that every other line should be blank, leaving sufficient whitespace to allow for annotation (i.e. from a teacher's corrections.)