English

Noun

chromo ‎(plural chromos)

1. (chiefly historical) A color print produced by chromolithography
   • 1870, Various, Punchinello Vol. 1, No. 21, August 20, 1870:

     All Nature is smiling, in fact, with one large, comprehensive smile, exactly like a first-class PRANG chromo with a fresh coat of varnish upon it.

   • 1883, Mark Twain (Samuel Clemens), Life on the Mississippi:

     It was manifest that we all felt that we ought to send the poor shoemaker SOMETHING. There was long and thoughtful discussion of this point; and we finally decided to send him a chromo.

   • 1999 February 19, Deanna Isaacs, “On Exhibit: a treasure trove of Mexican pop art”, in Chicago Reader:

     The neglected warehouse turned out to be a treasury of calendar art from the 1930s through the 1970s, years when chromo art calendars were a major advertising medium, a vehicle for national pride, and a fixture in nearly every home, business, and school.

Etymology 2

Noun

chromo ‎(plural chromos)

1. (chiefly Australia) A prostitute.
   • 1970, John Glassco, Memoirs of Montparnasse, New York 2007, p. 81:

     That dried-up lady snob lived behind lace curtains all her life. She's of no more importance than a chromo.

Etymology 3

From chromodomain.

Adjective

chromo ‎(not comparable)

1. (genetics) Of or relating to the chromodomain, a protein structural domain associated with chromatin production
   • 1998 April 24, Angus I. Lamond & William C. Earnshaw, “Structure and Function in the Nucleus”, in Science, volume 280, number 5363, DOI:10.1126/science.280.5363.547, pages 547-553:

     HP1 shares an ~50-amino acid NH 2 -terminal sequence motif, the chromo domain, with polycomb, an important regulatory gene that functions in the stable repression of homeotic genes during Drosophila development (28 ).

   • 2001 April 6, Jun-ichi Nakayama et al., “Role of Histone H3 Lysine 9 Methylation in Epigenetic Control of Heterochromatin Assembly”, in Science, volume 292, number 5514, DOI:10.1126/science.1060118, pages 110-113:

     To determine whether the conserved domains, the chromo, SET, and cysteine-rich regions, were also critical for Clr4 HMTase activity, we tested mutant Clr4 proteins for HMTase activity.