Malachim was an alphabet published by Heinrich Cornelius Agrippa in the 16th century. Other alphabets with a similar origin are the Celestial Alphabet and Transitus Fluvii.
"Malachim" is a plural form from Hebrew (מלאך, mal'ach) and means "angels" or "messengers", see Angels in Judaism.
History
The Malachim alphabet is derived from the Hebrew and Greek alphabets. It was created by Heinrich Cornelius Agrippa in the 16th century. It is still used by high degree Freemasons to a limited extent.