hang out one's shingle, to

hang out one's shingle

Open an office, especially a professional practice, as in Bill's renting that office and hanging out his shingle next month. This American colloquialism dates from the first half of the 1800s, when at first lawyers, and later also doctors and business concerns, used shingles for signboards.
See also: hang, out, shingle
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

hang out one's shingle, to

To open an office, especially a professional practice. This term comes from nineteenth-century America, when lawyers, doctors, and various business concerns often used actual shingles for signboards. Van Wyck Brooks, in The World of Washington Irving (1944), wrote, “Catlin hung out his shingle as a portrait-painter.”
See also: hang, out
The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer
See also: