This is a difficult word to trace down. Apparently is from the Apocrypha, and I cannot find it in the KJV Bible. ISBE wants to refer it to the word “Altar”. Most probably was the name of a person though. The Immer reference in ISBE in Logos is a glitch and has nothing to do with anything.
AALAR. KJV and ASV Apoc. (1 Esd 5:36) form of Immer.
1Esdras 5:36 There were 652 who returned from the families of Nekoda and of Delaiah son of Tobiah, though they could not prove they were Israelites. They had lived in the Babylonian towns of Tel-Melah and Tel-Harsha, and their leaders were Cherub, Addan, and Immer.