. (Physics & Chem.) a particle emitted at high velocity from certain radioactive substances. It is identical to the helium nucleus, consisting of two protons and two neutrons. Rays of such particles are called alpha rays. [ Webster 1913 Suppl. +PJC ]

n. (Physics) A fundamental particle which has the same mass as one of the common fundamental particles, but which has an opposite charge, and for which certain other of the properties (e. g. baryon number, strangeness) may be opposite to that of the normal particle. The antiparticle to an electron is called a positron; the antiparticle to a proton is called an antiproton; the antiparticle to a neutron is called an antineutron. When a particle and its corresponding antiparticle collide, they typically annihilate each other with the production of large quantities of energy, usually in the form of radiation. The interaction of a proton and antiproton cause annihilation with production of mesons. [ PJC ]

n. [ F., fr. L. articulus, dim. of artus joint, akin to Gr. &unr_;, fr. a root ar to join, fit. See Art, n. ] 1. A distinct portion of an instrument, discourse, literary work, or any other writing, consisting of two or more particulars, or treating of various topics; as, an article in the Constitution. Hence: A clause in a contract, system of regulations, treaty, or the like; a term, condition, or stipulation in a contract; a concise statement; as, articles of agreement. [ 1913 Webster ]

2. A literary composition, forming an independent portion of a magazine, newspaper, or cyclopedia. [ 1913 Webster ]

3. Subject; matter; concern; distinct. [ Obs. ] [ 1913 Webster ]

A very great revolution that happened in this article of good breeding. Addison. [ 1913 Webster ]

This last article will hardly be believed. De Foe. [ 1913 Webster ]

4. A distinct part. “Upon each article of human duty.” Paley. “Each article of time.” Habington. [ 1913 Webster ]

The articles which compose the blood. E. Darwin. [ 1913 Webster ]

5. A particular one of various things; as, an article of merchandise; salt is a necessary article. [ 1913 Webster ]

They would fight not for articles of faith, but for articles of food. Landor. [ 1913 Webster ]

6. Precise point of time; moment. [ Obs. or Archaic ] [ 1913 Webster ]

This fatal news coming to Hick's Hall upon the article of my Lord Russell's trial, was said to have had no little influence on the jury and all the bench to his prejudice. Evelyn. [ 1913 Webster ]

7. (Gram.) One of the three words, a, an, the, used before nouns to limit or define their application. A (or an) is called the indefinite article, the the definite article. [ 1913 Webster ]

8. (Zool.) One of the segments of an articulated appendage. [ 1913 Webster ]

Articles of Confederation, the compact which was first made by the original thirteen States of the United States. They were adopted March 1, 1781, and remained the supreme law until March, 1789. --
Articles of impeachment, an instrument which, in cases of impeachment, performs the same office which an indictment does in a common criminal case. --
Articles of war, rules and regulations, fixed by law, for the better government of the army. --
In the article of death [ L. in articulo mortis ], at the moment of death; in the dying struggle. --
Lords of the articles (Scot. Hist.), a standing committee of the Scottish Parliament to whom was intrusted the drafting and preparation of the acts, or bills for laws. --
The Thirty-nine Articles, statements (thirty-nine in number) of the tenets held by the Church of England. [ 1913 Webster ]

v. t. [ imp. & p. p. Articled p. pr. & vb. n. Articling ] [ Cf. F. articuler, fr. L. articulare. See Article, n., Articulate. ] 1. To formulate in articles; to set forth in distinct particulars. [ 1913 Webster ]

If all his errors and follies were articled against him, the man would seem vicious and miserable. Jer. Taylor. [ 1913 Webster ]

2. To accuse or charge by an exhibition of articles. [ 1913 Webster ]

He shall be articled against in the high court of admiralty. Stat. 33 Geo. III. [ 1913 Webster ]

3. To bind by articles of covenant or stipulation; as, to article an apprentice to a mechanic. [ 1913 Webster ]

v. i. To agree by articles; to stipulate; to bargain; to covenant. [ R. ] [ 1913 Webster ]

Then he articled with her that he should go away when he pleased. Selden. [ 1913 Webster ]

a. Bound by articles; apprenticed; as, an articled clerk. [ 1913 Webster ]

n. [ L. particula, dim. of pars, gen partis, a part: cf. F. particule. See Part, and cf. Parcel. ] 1. A minute part or portion of matter; a morsel; a little bit; an atom; a jot; as, a particle of sand, of wood, of dust. [ 1913 Webster ]

The small size of atoms which unite
To make the smallest particle of light. Blackmore. [ 1913 Webster ]

2. Any very small portion or part; the smallest portion; as, he has not a particle of patriotism or virtue. [ 1913 Webster ]

The houses had not given their commissioners authority in the least particle to recede. Clarendon. [ 1913 Webster ]

3. (R. C. Ch.) (a) A crumb or little piece of consecrated host. (b) The smaller hosts distributed in the communion of the laity. Bp. Fitzpatrick. [ 1913 Webster ]

4. (Gram.) A subordinate word that is never inflected (a preposition, conjunction, interjection); or a word that can not be used except in compositions; as, ward in backward, ly in lovely. [ 1913 Webster ]

4. (Physics) An elementary particle. [ PJC ]

n. (Physics) A large and expensive scientific instrument used by physicists to accelerate elementary particles (such as protons or electrons) to speeds near that of light, for the purpose of investigating the fundamental properties of matter; sometimes also called an atom smasher, since the particles thus accelerated are often directed at targets of atoms which are fragmented by the impact into their more fundamental component particles. The particles generated by impact of a beam in an accelerator on its target are detected by various types of detecting apparatus, and procedures are required to sort and identify the many particles created. The fundamental particles generated by impacts in a particle accelerator are often those not actually present inside atoms; and in certain types of particle accelerator, such as the colliding beam accelerator, the impact which generates energetic particles is with other fundamental particles, and not with atoms. [ PJC ]

n. That branch of physics which investigates the nature of matter, and in particular the properties and behavior of the elementary particles (fundamental particles), of which matter is composed. Included in this field is the more specialized branch of high-energy physics. [ PJC ]