A lot vs. Alot: 9 Grammatical Pitfalls
c.1300, "communication transmitted via a messenger," from Old French message "message, news, tidings, embassy" (11c.), from Medieval Latin missaticum, from Latin missus "a sending away, sending, despatching; a throwing, hurling," noun use of past participle of mittere "to send" (see mission). The Latin word is glossed in Old English by ærende. Specific religious sense of "divinely inspired communication via a prophet" (1540s) led to transferred sense of "the broad meaning (of something)," first attested 1828. To get the message "understand" is from 1960.
To send a message on the Internet •The sense ''to send a message'' is found by 1583: '' I need to do it,'' Baker messaged a man with whom he had been discussing rape, torture, and murder (1990s+ Computer)
In object-oriented programming sending a message to an object (to invoke a method) is equivalent to calling a procedure in traditional programming languages, except that the actual code executed may only be selected at run time depending on the class of the object. Thus, in response to the message "drawSelf", the method code invoked would be different if the target object were a circle or a square.