Early morning; dawn. Mom knows you were out till the early beam last night, so don't try to hide it.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
See early beams
n. dawn; early morning. (Streets.) He was away every day, early black to early beam.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.