Greeting

Greeting is a way for human beings (as well as other members of the animal kingdom) to intentionally communicate awareness of each other's presence, to show attention to, and/or to affirm or suggest a type of relationship or social status between individuals or groups of people coming in contact with each other. As with many forms of communication, greeting habits are highly culture- and situation-specific and may change within a culture depending on social status and relationship; the phenomenon as such exists in all known human cultures, though. Greetings can be expressed both audibly and physically, and often involve a combination of the two. This topic excludes military and ceremonial salutes but includes rituals other than gestures.

Greetings are often, but not always, used just prior to a conversation.

Some epochs and cultures had very elaborate greeting rituals, e.g., greeting of a king.

Secret societies have clandestine greeting rituals that allow members to recognize common membership.

Spoken greetings are customary or ritualised words or phrases used to introduce oneself or to greet someone. In English, some common verbal greetings are:

• "Hello" — the most common verbal greeting in English-speaking countries, and related to "Hullo" (UK English, now old-fashioned) and "Hallo". Suitable for formal and informal usage.
• "Hi", related to "Hiya", both being less formal for 'hello' but very widely used nowadays. It is classified in dictionaries as a sentence substitute. "Hi" is relatively new, having become popular in the 1920s in the USA and then spread throughout English-speaking populations around the world, and even into other languages.
• "hey", has become fairly commonplace as a greeting in informal USA English, but is considered impolite in UK English to use as a greeting (Cambridge English dictionary says "used as a way of attracting someone's attention, sometimes in a way which is not very polite"; its standard usage in the UK is to express a mixture of surprise and displeasure/indignation/protest/reprimand, or else to shout (specifically not at standard spoken volume) at someone from afar prior to greeting them or else warning them about danger. According to the Cambridge English and Collins English dictionaries "hey" is not used as a greeting, but an interjection used to express surprise (sometimes with indignation or displeasure, e.g. "Hey, stop that!" or "Hey, stop making a noise! or "Hey, what do you think you're doing?!"), inquiry (as a prelude, thus catching attention, e.g. "Hey, have you seen this?"), interest (especially sudden, e.g. "Hey, what's going on?!"), and to call attention from a distance (e.g. across the street, or when someone's back is turned - "Hey, didn't see you there!" or "Hey, over here!"). It is also used in popular song lyrics, and in idiomatic phrases such as 'Hey presto!'.
• "Good morning", "Good afternoon", "Good evening" — More formal verbal greetings used at the appropriate time of day. Note that the similar "Good night" and "Good day" are more commonly used as phrases of parting rather than greeting. These are often abbreviated by those wishing to be less formal, e.g. amongst friends or family, to 'Morning!', 'Afternoon!', 'Night!' or 'G'night!'
• "How do you do?", along with variations such as "Howrya" (Ireland) and "Hiya"
• "Howdy" — Informal greeting. Derived from "How do you do," it is common in the rural regions of the United States. This is also the official greeting of the Texas A&M Aggies of Texas A&M University in College Station, Texas.
• "What's up?", "Whassup", "Sup?", "How's it going?", "Yo", and "What's happenin?" — United States. "How's tricks?" and "How's it going?" are popular in UK English, but note that 'What's up?' in UK English means 'What's wrong?' and is therefore not a greeting.