v. i. [ imp. & p. p. Cohered p. pr. & vb. n. Cohering ] [ L. cohaerere, cohaesum; co- + haerere to stick, adhere. See Aghast, a. ] 1. To stick together; to cleave; to be united; to hold fast, as parts of the same mass. [ 1913 Webster ]

Neither knows he . . . how the solid parts of the body are united or cohere together. Locke. [ 1913 Webster ]

2. To be united or connected together in subordination to one purpose; to follow naturally and logically, as the parts of a discourse, or as arguments in a train of reasoning; to be logically consistent. [ 1913 Webster ]

They have been inserted where they best seemed to cohere. Burke. [ 1913 Webster ]

3. To suit; to agree; to fit. [ Obs. ] [ 1913 Webster ]

Had time cohered with place, or place with wishing. Shak.

Syn. -- To cleave; unite; adhere; stick; suit; agree; fit; be consistent. [ 1913 Webster ]

{ , n. [ L. cohaerentia: cf. F. cohérence. ] 1. A sticking or cleaving together; union of parts of the same body; cohesion. [ 1913 Webster ]

2. Connection or dependence, proceeding from the subordination of the parts of a thing to one principle or purpose, as in the parts of a discourse, or of a system of philosophy; a logical and orderly and consistent relation of parts; consecutiveness. [ 1913 Webster ]

Coherence of discourse, and a direct tendency of all the parts of it to the argument in hand, are most eminently to be found in him. Locke. [ 1913 Webster ]

3. the state of cohering.
Syn. -- cohesion, cohesiveness. [ WordNet 1.5 ]

a. [ L. cohaerens, p. pr. See Cohere. ] 1. Sticking together; cleaving; as the parts of bodies; solid or fluid. Arbuthnot. [ 1913 Webster ]

2. Composed of mutually dependent parts; making a logical whole; consistent; as, a coherent plan, argument, or discourse. [ 1913 Webster ]

3. Logically consistent; -- applied to persons; as, a coherent thinker. Watts. [ 1913 Webster ]

4. Suitable or suited; adapted; accordant. [ Obs. ] [ 1913 Webster ]

Instruct my daughter how she shall persever,
That time and place, with this deceit so lawful,
May prove coherent. Shak. [ 1913 Webster ]

5. (Physics, Optics) Of or pertaining to electromagnetic waves that have a constant phase relationship with each other; having identical phase at all points; as, the coherent light produced by a laser. [ PJC ]

n. (Physics, Optics) Light in which the phases of all electromagnetic waves at each point on a line normal to the direction of the the beam are identical. Coherent light is usually monochromatic, and the most common source of such light for practical uses is from a laser. The constant phase relations of coherent light allows the achievement of certain effects, such as holography, not possible with noncoherent light. The low degree of angular dispersion of coherent light beams also allows the use of such light in laser ranging, over distances as far as from the earth to the moon. [ PJC ]

adv. In a coherent manner. [ 1913 Webster ]

n. (Elec.) Any device in which an imperfectly conducting contact between pieces of metal or other conductors loosely resting against each other is materially improved in conductivity by the influence of Hertzian waves; -- so called by Sir O. J. Lodge in 1894 on the assumption that the impact of the electic waves caused the loosely connected parts to cohere, or weld together, a condition easily destroyed by tapping. A common form of coherer as used in wireless telegraphy consists of a tube containing filings (usually a pinch of nickel and silver filings in equal parts) between terminal wires or plugs (called
conductor plugs). [ Webster 1913 Suppl. ]