"cotton cloth printed with flowers or other colorful patterns," 1719, plural of chint (1610s), from Hindi chint, from Sanskrit chitra-s "clear, bright" (compare cheetah). The plural (the more common form of the word in commercial use) came to be regarded as singular by late 18c., and for unknown reason shifted -s to -z; perhaps after quartz. Disparaging sense, from the commonness of the fabric, is first suggested by 1851 (in George Eliot's use of chintzy).
The term chintz-work is descriptive of that kind of calico-printing which is employed for beds, window-curtains, and other furniture, and it differs more in the richness and variety of the colours, than in any other circumstance. [Abraham Rees, "Cyclopaedia," 1819]
digraph used in Old French for the "tsh" sound. In some French dialects, including that of Paris (but not that of Picardy), Latin ca- became French "tsha." This was introduced to English after the Norman Conquest, in words borrowed from Old French such as chaste, charity, chief (adj.). Under French influence, -ch- also was inserted into Anglo-Saxon words that had the same sound (such as bleach, chest, church) which in Old English still was written with a simple -c-, and into those that had formerly been spelled with a -c- and pronounced "k" such as chin and much.
It turns up as well in words from classical languages (chaos, echo, etc.). Most uses of -ch- in Roman Latin were in words from Greek, which in Greek would be pronounced correctly as /k/ + /h/, as in modern blockhead, but most Romans would have said merely /k/, and this was the regular pronunciation in English. Before c. 1500 such words were regularly spelled with a -c- (Crist, cronicle, scoole), but Modern English has preserved or restored the etymological spelling in most of them (chemical, chorus, monarch).
Sometimes ch- is written to keep -c- hard before a front vowel, as still in modern Italian. In some languages (Welsh, Spanish, Czech) ch- can be treated as a separate letter and words in it are alphabetized after -c- (or, in Czech and Slovak, after -h-). The sound also is heard in words from more distant languages (as in cheetah, chintz), and the digraph also is used to represent the sound in Scottish loch.