flatly (part of speech: adverb)
- " After advancing persistently and almost horizontally along the face of the wall for two hours, we saw an unexpected chance of reaching our goal more speedily than we had latterly hoped. - "Among the Canadian Alps", Lawrence J. Burpee.
- Some are sweeter- tempered than others, and seem pointed horizontally, if not heavenward, in their natures. - "From Jest to Earnest", E. P. Roe.
- After 1700, the sliding sash was introduced, dividing the windows horizontally, and these had wooden muntins. - "Remodeled Farmhouses", Mary H. Northend.