Wiktionary
single-spaced
vb. (en-past of: single-space)
WordNet
single-spaced
adj. (of type or print) not having a blank space between lines; "business letters are usually single-spaced"
Usage examples of "single-spaced".
This reply ran to sixty-two single-spaced pages, and neither Doyle nor any of his officers could either understand it as it stood, or break it down into anything they could understand.
He unwound the packet until it was flat, unzipped the inner lining, and withdrew two sheets of single-spaced typing.
Foley handed over a single printed page, about five hundred single-spaced words once you got past the cover sheet.