[f. LINK sb.2 or v.1 + -AGE.] The condition or manner of being linked; a system of links.
Applied e.g. (Chem.) to the union of atoms or radicals in a molecule; (Geom.) to a system of straight lines, etc., pivoted together so as to rotate about one another (by Sylvester used with restricted application; see quot. 1874 for link-work, LINK sb.2 7).
1874. Sylvester, in Proc. Roy. Instit., VII. 182, note. A compass or a pair of scissors is the simplest form of linkage; a set of lazy-longs is another.
1877. Kempe (title), How to draw a straight line; a lecture on linkages.
1887. Jrnl. Franklin Inst., Jan., 74. Brühl showed that in case of ‘double-linkage’ each such carbon-atom has a refraction equivalent to about 6·1.
1890. Spectator, 11 Sept., 462/1. Chemists are persuaded that the ethylenic form of linkage is not the equivalent of two paraffinic linkages.
1893. Cayley, in Coll. Math. Papers (1897), XIII. 292. The results given by the MacMahon linkage.
1897. Standard, 1 Feb., 5/2. The linkage of life to life in Nature.
1899. Allbutt’s Syst. Med., VI. 512. Such places of linkage of neurons being called ‘synapses.’
