What does diagonally mean?
"Diagonally" is an adverb describing movement, placement, or orientation along a diagonal — that is, at a slanting angle rather than straight up-and-down or side-to-side. It is most commonly used for the corner-to-corner path across a square or rectangular shape: a line drawn diagonally across a page, a street running diagonally through a city grid, or a bishop moving diagonally on a chessboard. The word carries no particular emotional connotation; it is precise, neutral, and functional, appearing naturally in mathematics, geometry, sports, crafts, design, and everyday description. Its usefulness lies in conveying direction economically: saying a stripe runs diagonally instantly tells the reader both that it is angled and that it crosses a surface obliquely. Related forms include the noun and adjective "diagonal." Derived from Greek via Latin, the root literally means "from angle to angle," which is exactly how the word behaves today.
adverbIn a slanting or oblique direction, from one corner of a shape, surface, or space to the opposite one; at an angle rather than parallel or perpendicular.
- In a slanting or oblique direction across a surface or space, especially from corner to corner of a square or rectangular shape.
- At an angle intermediate between two other directions, such as between vertical and horizontal.
"She cut the sandwich diagonally so each half had a crisp corner."
"The scar ran diagonally across his left cheekbone from temple to jaw."
"Fold the fabric diagonally to create a triangular piece."
Every chess bishop's entire career is spent moving diagonally — which is why it can only ever reach half the squares on the board.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of diagonally
The word traces back through French "diagonal" to Latin "diagonalis," derived from Greek "diagonios" (διάγωνιος), meaning "from angle to angle," formed from "dia-" (through, across) and "gonia" (angle). The adverb form developed in English alongside the adjective, becoming established by the early modern period as geometric terminology entered general usage. Cognate formations sharing the same "dia-" prefix include "diameter" and "diagram."
Related word forms
How diagonally is actually used
A neutral, everyday word common in both speech and writing; frequent in geometry, games (especially chess), sewing, design, and physical description. No significant regional variation in meaning or register.
Easily confused with diagonally
'Diagonal' is the adjective or noun describing the slanting line itself, while 'diagonally' is the adverb describing movement or orientation in that manner.