I recently started working in a place in Berlin, Germany, and though my German is OK I guess, there's a common term that I don't understand. It's Mahlzeit.
When people leave from work around lunch time, they say that and people around respond with the same. According to dict.cc it means "Enjoy your meal!".
Is this a common German term or is it just a thing in Berlin? What does it mean exactly? And do you have to respond with Mahlzeit or are there other responses one may use?
It's not restricted to Berlin. Mahlzeit consists of Mahl (=process of eating) and Zeit (=time). So it refers to "the time when you eat" (=mealtime) and is technically not limited to lunchtime.
However, it's widely used as kind of a greeting around lunchtime. So, even if you meet someone outside around lunchtime, you could say Mahlzeit. This is acceptable since you're assuming that they're going to have lunch.
I haven't heard it when leaving the office, though; it's more of a greeting rather than goodbye.
A proper respond is, of course, Mahlzeit; or you say Danke when you are already eating as it then really means "Enjoy your meal".
See also: http://jakubmarian.com/how-to-use-mahlzeit-in-german/
In addition to the other answers:
Sometimes the business etiquette is complicated when we meet a colleague multiple times (See e.g. the section Grüßt man sich erneut, wenn man sich im Flur trifft?). It is a bit strange if you repeat a Guten Morgen or Guten Tag each time you meet somebody on the same day. (The link recommend to nod)
With Mahlzeit you have an adequate greeting if you meet somebody again and you don't want to repeat the greeting you already used in the morning.
During the day you could start with Guten Morgen, followed by a Mahlzeit during lunch time and in the evening you can close with a Schönen Feierabend or Auf Wiedersehen if you or your colleague leaves the work.
In industrial environments — especially in automobile industry — “Mahlzeit” often simply means “hello”.
Even most Germans who are not working in such companies do not know about this.
When starting a new job in such a company they are a bit confused because they understand: “I wish you a tasteful lunch” instead of: “hello”.
The response to the greeting Mahlzeit differs from company to company.
In companies where Mahlzeit means hello you can simply respond with Mahlzeit, too.
In environments where Mahlzeit means “I wish you a tasteful lunch” you simply respond with “Danke”.
In a company I have worked for the response was sometimes:
Mahl’ deine Zeit selber
(Because “Mahl’ Zeit” would mean “grind time”, so the response is “grind your time yourself”).
However you should never respond this way unless you are absolutely sure that this is the correct way to respond in the company you are working at!
For me its easy, you say "Mahlzeit" mainly at lunchtime in German.
You say it when someone begins his break at work, when you encounter someone at lunch or simply if you believe someone will have lunch break or just had lunch.
When someone says "Mahlzeit" to you and you are going to have lunch or just had lunch just reply "Mahlzeit" back,o otherwise just say "Danke"- "thanks"
In German "Mahlzeit" is used like a question and a greeting together. It says "I'll have lunch now, you too?" or "i wish you a good appetite or lunchtime"
CAUTION: Do not use this in meetings as it is very informal. Use only with friends or acquaintances.
I assume, that your questions addresses Mahlzeit used on its own, without any additions.
Two additions concerning other uses.
1) It is used as generic term for any of breakfast, lunch and dinner.
Vor den Mahlzeiten einzunehmen (e.g. for medicine: take before instead of after eating)
2) One combination has a non-intuitive meaning:
Prost Mahlzeit!
This does NOT mean "enjoy your meal and drink" but is more like "Anything fouled up".
Mahlzeit may also have a negative meaning similar to the American oh, forget it. For a good example see this Youtube video (start at 21:11 for context)
