Mokum (מקום) is the Yiddish word for "place" or "safe haven". It is similar to the Hebrew word makom (מקום, "place"), from which it is derived. In Yiddish the names of some cities in the Netherlands and Germany were shortened to Mokum and had the first letter of the name of the city, transliterated into the Hebrew alphabet, added to them. Cities named this way were Amsterdam, Berlin, Delft, and Rotterdam.
Mokum, without Aleph, is still used as a nickname for Amsterdam. The nickname was first considered to be Bargoens, a form of Dutch slang, but in the 20th century it lost its negative sound and is now used as a nickname for Amsterdam in a sentimental context.