Assemblage, n.
Etymology: [Cf. F. assemblage. See Assemble.]
1. The act of assembling, or the state o In sweet assemblage every blooming grace. Fenton.
2. A collection of individuals, or of individuals, or of particular things; as, a political assemblage; an assemblage of ideas.
Syn. -- Company; group; collection; concourse; gathering; meeting; convention. Assemblage, Assembly. An assembly consists only of persons; an assemblage may be composed of things as well as persons, as, an assemblage of incoherent objects. Nor is every assemblage of persons an assembly; since the latter term denotes a body who have met, and are acting, in concert for some common end, such as to hear, to deliberate, to unite in music, dancing, etc. An assemblage of skaters on a lake, or of horse jockeys at a race course, is not an assembly, but might be turned into one by collecting into a body with a view to discuss and decide as to some object of common interest.
Shades of meaning
Fernald has no entry of its own for assemblage; he lists it under company.
Where he writes about it:
Company, from the Latin cum, with, and panis, bread, denotes primarily the association of those who eat at a common table, or the persons so associated, table-companions, messmates, friends, and hence is widely extended to include any association of those united permanently or temporarily, for business, pleasure, festivity, travel, etc., or by sorrow, misfortune, or wrong; company may denote an indefinite number (ordinarily more than two), but less than a multitude; in the military sense a company is a limited and definite number of men; company implies more unity of feeling and purpose than crowd, and is a less formal and more familiar word than assemblage or assembly. — from company
An assemblage may be of persons or of objects; an assembly is always of persons. — from company
An assemblage is promiscuous and unorganized; an assembly is organized and united in some common purpose. — from company
Collection, crowd, gathering, group, and multitude have the unorganized and promiscuous character of the assemblage; the other terms come under the general idea of assembly. — from company