greeting between persons meeting, 1848, early references are to the U.S. western frontier (where hello, the house was said to be the usual greeting upon approaching a habitation).

It is an alteration of hallo, itself an alteration of holla, hollo, a shout to attract attention, which seems to go back at least to late 14c. (compare Middle English verb halouen "to shout in the chase," hallouing). OED cites Old High German hala, hola, emphatic imperative of halon, holon "to fetch," "used especially in hailing a ferryman." Fowler in the 1920s listed halloo, hallo, halloa, halloo, hello, hillo, hilloa, holla, holler, hollo, holloa, hollow, hullo, and writes, "The multiplicity of forms is bewildering ...."

Its rise to popularity as a greeting (1880s) coincides with the spread of the telephone, where it won out as the word said in answering, over Alexander Graham Bell's suggestion, ahoy. Central telephone exchange operators were known as hello-girls (1889).