chlorine: [19] Chlorine is a greenish-yellow gas, and was named for its colour. The term was coined by the British chemist Sir Humphry Davy in 1810, from the Greek khlōrós ‘greenishyellow’. Of other words containing this element, chlorophyll [19] too was based on the notion of colour (in reference to the green colouring matter of leaves: the Greek elements literally mean ‘green leaf’), but chloroform [19], originally French, is a secondary formation based ultimately on chlorine (since it was originally regarded as a trichloride of formyl). => yellow[chlorine etymology, chlorine origin, 英语词源]