Say hi, in slang

• Shout-out word
• "Hit me up"
• Modern word of salute
• A very loud utterance (like the sound of an animal)
• Casual greeting

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Holla \Hol"la\, interj. [F. hola; ho ho + l[`a] there, fr. L. illac that way, there. Cf. Hollo .] Hollo.

WordNet Word definitions in WordNet
n. a very loud utterance (like the sound of an animal); "his bellow filled the hallway" [syn: bellow , bellowing , holler , hollering , hollo , holloa , roar , roaring , yowl ]

Wiktionary Word definitions in Wiktionary
Etymology 1 interj. (alternative form of hollo English) vb. (alternative form of hollo English) Etymology 2 interj. (context colloquial English) what's up; a greeting vb. (context colloquial English) To shout out or greet casually.

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
as a command to "stop, cease," 1520s, from French holà (15c.). As a command to get attention, from 1580s. As an urban slang form of holler (v.) and meaning "greet, shout out to," it was in use by 2003.