arch.

Collins Concise English Dictionary © HarperCollins Publishers::

arch. abbreviation

1. archaic
2. archaism

WordReference Random House Learner's Dictionary of American English © 2025

arch¹ /ɑrtʃ/  n. [countable]

1. Architecture a curved construction over an opening.
2. Architecture a doorway, gateway, or opening having a curved head;
   archway.
3. anything bowed or curved like an arch:
   the arch of the foot.

v. 

4. to form (into) an arch: [no object]
   The elms arched over the road.
   [~ + object]
   The cat arched its back as a warning.

arch² /ɑrtʃ/   adj. 

1. crafty;
   sly;
   mischievous or cunning:
   an arch little grin.
2. chief;
   main:
   They were arch foes.

arch•ly, adv. 
arch•ness, n. [uncountable]

-arch-, root. 

1. -arch- comes from Greek, where it has the meaning "chief;
   leader;
   ruler.'' This meaning is found in such words as: anarchy, archbishop, archdiocese, hierarchy, matriarch, monarch, monarchy, patriarch.
2. -arch- is also used to form nouns that refer to persons who are the most important, most notable, or the most extreme examples of (the following noun): archenemy (= the most important enemy);
   archconservative (= the most extreme example of a conservative).
3. -arch- also appears with the meaning "first, earliest, original, oldest in time.'' This meaning is found in such words as: archaeology, archaic, archaism, archetype.

arch.,  an abbreviation of:

1. archaic.
2. Architecture architect.
3. Architecture architecture.

WordReference Random House Unabridged Dictionary of American English © 2025

arch¹  (ärch), n. 

1. Architecture
   • Architecture a curved masonry construction for spanning an opening, consisting of a number of wedgelike stones, bricks, or the like, set with the narrower side toward the opening in such a way that forces on the arch are transmitted as vertical or oblique stresses on either side of the opening.
   • Architecture an upwardly curved construction, as of steel or timber functioning in the manner of a masonry arch.
   • Architecture a doorway, gateway, etc., having a curved head;
     an archway.
   • Architecture the curved head of an opening, as a doorway.
2. any overhead curvature resembling an arch.
3. something bowed or curved;
   any bowlike part:
   the arch of the foot.
4. Clothing a device inserted in or built into shoes for supporting the arch of the foot.
5. Civil Engineering a dam construction having the form of a barrel vault running vertically with its convex face toward the impounded water.
6. Ceramics [Glassmaking.]
   • a chamber or opening in a glassmaking furnace.
   • See pot arch. 

v.t. 

7. to cover with a vault, or span with an arch:
   the rude bridge that arched the flood.
8. to throw or make into the shape of an arch or vault;
   curve:
   The horse arched its neck.

v.i. 

9. to form an arch:
   elms arching over the road.
10. Nautical, Naval Terms hog (def. 16).

• Vulgar Latin *arca, feminine variant of Latin arcus arc
• Old French arche
• Middle English arch(e) 1250–1300

arch²  (ärch), adj. 

1. playfully roguish or mischievous:
   an arch smile.
2. cunning;
   crafty;
   sly.

n. 

3. [Obs.] a person who is preeminent;
   a chief.

• independent use of arch-¹

arch-¹ :

1. a combining form that represents the outcome of archi- in words borrowed through Latin from Greek in the Old English period;
   it subsequently became a productive form added to nouns of any origin, which thus denote individuals or institutions directing or having authority over others of their class (archbishop;
   archdiocese;
   archpriest). More recently, arch- ¹ has developed the senses "principal'' (archenemy;
   archrival) or "prototypical'' and thus exemplary or extreme (archconservative);
   nouns so formed are almost always pejorative.

• Greek. Cf. archangel
• Medieval Latin arci-, and Gothic ark- directly
• Greek (see archi-); but Dutch aarts-, Middle Low German erse-, Middle High German, German Erz-
• Latin archi-
• Old English arce-, ærce-, erce- ( Old Norse erki-) Middle English

arch-² :

1. var. of archi- before a vowel:
   archangel; archenteron.

-arch, 

1. a combining form meaning "chief, leader, ruler,'' used in the formation of compound words:
   monarch;
   matriarch;
   heresiarch.

• Greek -archos or -archēs, as comb. forms of árchos leader; compare archi-

Arch., 

1. Archbishop.

arch., 

1. archaic.
2. archaism.
3. Sport archery.
4. archipelago.
5. Architecture architect.
6. Architecture architectural.
7. Architecture architecture.
8. archive;
   archives.