Company name (Firma)
Also: Firma, Firmierung, Firmenname, business name, trade name
In short
In the legal sense, the "Firma" is the name under which a merchant conducts business and signs. It must be distinctive, must not be misleading and must contain the legal form suffix.
Company name (Firma) explained
In everyday German, "Firma" means the whole business; legally, it only means its name (Sec. 17 (1) HGB). Personal, descriptive and invented names are possible, as long as the name is suitable for identification, is distinctive and is not misleading about essential business circumstances (Sec. 18 HGB). The legal form suffix is mandatory, for example "GmbH", "UG (haftungsbeschränkt)", "e.K.", "OHG" or "KG" (Sec. 19 HGB, Sec. 4, 5a GmbHG). A GbR does not carry on a commercial business and therefore has a name rather than a "Firma". Before forming, also check whether the name infringes an older trade mark, because a commercial register entry is not a trade mark.