List of 426 Sets of Synonyms - How they Differ - Total of 2307 Words - 414

SYNONYMS: vertical, upright, perpendicular, plumb.
These adjectives are compared as they mean being at or approximately at right angles to the horizon or to level ground.

Vertical and especially upright are often used to signify contrast with what is horizontal; the terms do not always imply an exact right angle: wallpaper with vertical stripes; an upright column.
Perpendicular and plumb are generally used to specify an angle of precisely 90 degrees: a perpendicular escarpment; careful to make the doorjambs plumb.