There are variants of HELLO in different contexts. See a few examples below.
Meaning: Used as a greeting or to begin a telephone conversation.
Meaning: HELLO EVERYONE (or ALL OF YOU). [Video contributed by Greg Eyben, 2016.]
Meaning: HELLO in a plural form. [Video contributed by LaDonna Snyder, 2017.]
It can be used as another variant for "HELLO EVERYONE" in some contexts or as a big greeting "MANY or BIG HELLOs!" in other contexts.
Review 101 words. Refresher.