1715 (intransitive); 1722 (transitive), probably an alteration of plash with an intensive s-. Related: Splashed; splashing. Splash-board attested from 1826. Splash-down (n.) in the spacecraft sense is attested from 1961.[splash etymology, splash origin, 英语词源]
1736, "water or liquid thrown upon anything," from splash (v.). Meaning "striking or ostentatious display" is first attested 1804. Sense of "small quantity of soda water, etc., added to a drink" is from 1922. Of color or light, 1832.