Main entry: horizontal
Definition: parallel to or in the plane of the horizon or a base line
Usage: a horizontal surface
Antonyms: perpendicular, vertical
Definition: at right angles to the plane of the horizon or a base line
Antonyms: inclined
Definition: at an angle to the horizontal or vertical position
Antonyms: contrasty
Definition: having sharp differences between black and white
Antonyms: natural
Definition: (of a musical note) being neither raised nor lowered by one chromatic semitone
Antonyms: sharp
Definition: (of a musical note) raised in pitch by one chromatic semitone
Antonyms: set up, put up, raise, rear, erect
Definition: construct, build, or erect
Antonyms: lengthways, lengthwise
Definition: running or extending in the direction of the length of a thing