The country around Down House in Kent was nothing but ‘a congeries of muddy lanes’ according to Darwin’s eldest daughter Henrietta (1843-1927). I realised, shortly after reading this, that I had never uttered the word congeries and hardly knew how.
Recourse to the OED alarmed me. Congeries, it stated, is a word of four syllables, stressed on the second, and pronounced cn-JEER-i-eez. That is logical, considering that it comes directly from Latin congeries, ‘a heap or pile’. Its connotation of heterogeneity is often suggested by a preceding qualification, ‘mere’. A related Latin word for the same thing is congestus, and congeries is thus connected with the English congest, not very helpfully as far as elucidating the sense goes, since congested has meant ‘filled up by an obstructive accumulation; overcrowded’ only since the 19th century. Before that, it meant ‘heaped together, accumulated’. As an English word, congeries has the oddity of looking as though it might be plural, and of forming a plural identical in form to the singular (as with species). In any case, I practised a little saying ‘congeries’ as four syllables, but could not be sure that anyone would understand me if I used it. Consulting the New Fowler’s, I found that RW Burchfield regarded the four-syllable pronunciation as ‘old-fashioned’ (in 1996) and advised instead: cn-JEER-eez. Current books on American usage suggest that the common pronunciation there is CON-juhr-eez. This pronunciation takes leave of the etymology.
After a little straw poll of literate friends I found that none knew the precise meaning of the word or its pronunciation. One cleverly rooted out the title of a book: Nabokov’s Congeries (an omnibus published in 1968).