Clay·ton 
(klātn), John Middleton 1796-1856.
(klātn), John Middleton 1796-1856. American public official who as secretary of state (1849-1850) negotiated the Clayton-Bulwer Treaty with Great Britain (1850), establishing the neutrality of a proposed canal across Central America.
- echini
- echino-
- echinococcosis
- echinococcus
- echinoderm
- echinodermal
- echinodermatous
- echinoid
- echinus
- echo
- Echo
- echocardiogram
- echocardiograph
- echocardiographic
- echocardiography
- echo chamber
- echo check
- echoencephalogram
- echoencephalograph
- echoencephalographic
- echoencephalography
- echoer
- echoey
- echogram
- echography