Words related to hello
shout to call attention, 1781, earlier hollo, holla (also see hello). "Such forms, being mere syllables to call attention, are freely varied for sonorous effect" [Century Dictionary]. Old English had ea la. Halow as a shipman's cry to incite effort is from mid-15c.; Halloo as a verb, "to pursue with shouts, to shout in the chase," is from late 14c. Compare also harou, cry of distress, late 13c., from French.
1580s as a command to get attention, in which use it belongs in the group with hello, hallo. From 1520s as a command to "stop, cease," from French holà (15c.), which "Century Dictionary" analyzes as ho! + la "there." As an urban slang form of holler (v.) "greet, shout out to," it was in use by 2003.
1762, hollo-ballo (with many variant spellings) "uproar, racket, noisy commotion," chiefly in northern England and Scottish, perhaps a rhyming reduplication of hollo (see hello). Bartlett ("Dictionary of Americanisms," 1848) has it as hellabaloo "riotous noise; confusion," and says it is provincial in England.