Green’s Dictionary of Slang

main stem n.

[SE main stem, the central trunk]

1. (US) a person of importance, the boss.

[US]Ade Fables in Sl. (1902) 24: I was just Thinking what chance have I got to grow up and be the Main Stem, like Mr. Jeffries.
[US]Guilelmensian (Williams Coll.) 289: Some one asked him if he had ever seen a baseball, to which he replied that he had been the Main Stem of the Prep. school team.
[US]Number 1500 Life In Sing Sing 256: Main Stem. Head person.
Wodehouse ‘An International Affair’ in Politeness of Princes [ebook] ‘[T]hey come to us. Correct, sir. We are the main stem’.
[US]Monteleone Criminal Sl. (rev. edn).

2. (also big stem) the main street of a town.

[US]Flynt & Walton Powers That Prey 250: One can complete investigations that have been begun in ‘the main stem’ of towns thousands of miles away.
[US]J. London Road 160: The kids began ‘battering’ the ‘main-stem’ for ‘light pieces,’ or, in other words, begging for money on the main street.
[US]J. Lait ‘Canada Kid’ in Beef, Iron and Wine (1917) 181: It’s got me wingin’, too. I keep right on workin’—I lift a boob for $106.60 on a mainstem caboose yesterday.
[US]N. Anderson Hobo 3: They call it ‘The Main Stem,’ a term borrowed from tramp jargon, and meaning the main street of the town.
[US]P.J. Wolfson Bodies are Dust (2019) [ebook] ‘Big Stem James,’ [...] a familiar figure on the ‘Big Street’.
[US]M. Rand ‘Clip-Joint Chisellers’ in Ten Story Gang Aug. 🌐 As gold diggers they could chisel nicer and dig deeper than any two chippies on the big stem.
[UK]P. Cheyney Don’t Get Me Wrong (1956) 60: It is twelve o’clock an’ a sweet night, an’ I am walking down the main stem ponderin’.
[US]Mezzrow & Wolfe Really the Blues 138: Tin Pan Alley was soon to be the main stem in the music world.
[US]Mad mag. June–July 27: A dingy two-by-four office on the main stem.
[US]N. Algren Walk on the Wild Side 67: I go down the main stem and I’m on my way back to The Home by morning.
[US]Ragen & Finston World’s Toughest Prison 808: main stem – The main street or a town or city.
[US]O. Hawkins Ghetto Sketches 24: Saturday night ... any Saturday ... the main stem sizzles and crackles with the flicker of neon lights.
[US]I.L. Allen City in Sl. (1995) 41: The main drag or main stem originally was the main thoroughfare of hobohemias, such as the Bowery, rather than the principal and most central street of a town, such as Fifth Avenue or 42nd Street. But the terms in slang were generalized to the main street of a city, or to the main thoroughfare of some part of a large city.
[US](con. 1940s–60s) Décharné Straight from the Fridge Dad.

3. (US black) attrib. use of sense 2, stylish, sophisticated.

[US]W. Winchell Your Broadway & Mine 20 Nov. [synd. col.] The most interesting of the Main Stem topics at present is the Arnold Rothstein case.
[US]Pittsburgh Courier (PA) 29 Apr. 11/1: Mae Diggs [...] is being hired by a main stem nitery.
[US]T. Wolfe Electric Kool-Aid Acid Test (1969) 384: He has on tight black pants, black shark toe slip-on shoes, a soft black sweater and open-neck shirt . . . dressed Main Stem hipster, in short.

4. (US tramp) the most important street of a town in the context of tramp society and standards.

[US]W. Edge Main Stem 17: We are now on the ‘stem’ or ‘main stem’ or ‘main drag’ [...] The main stem is the principal street from the hobo’s point of view. It is not the main residential street; it is not the main business street; it is the hobo’s street [...] It is on this street that the homeless have put their stamp of approval.
[US]‘Dean Stiff’ Milk and Honey Route 209: Main stem – The chief hobo street in town.

5. Broadway, New York City.

Morn. Call (Allentown, PA) 8 Dec. 10/5: Broadway is known as ‘The Main Stem’.
[US]Cab Calloway New Hepsters Dict. in Calloway (1976) 252: apple (n.): the big town, the main stem, Harlem.
[US]I.L. Allen City in Sl. (1995) 41: The main drag or main stem originally was the main thoroughfare of hobohemias, such as the Bowery, rather than the principal and most central street of a town, such as Fifth Avenue or 42nd Street. But the terms in slang were generalized to the main street of a city, or to the main thoroughfare of some part of a large city. The theater district along Broadway was once called The Main Stem.

6. attrib. use of sense 5.

[US]W. Winchell On Broadway 31 Jan. [synd. col.] Loudspeakers in front of Main Stem music shops pouring out romantic tunes.
[US]W. Winchell On Broadway 18 Aug. [synd. col.] His wham click at the Capri is Main Stem gab.

In derivatives

mainstemmer (n.)

a man or woman ‘about town’.

[US]W. Winchell Your Broadway & Mine 3 Nov. [synd. col.] Mainstemmers are wagering that Alexander Woollcott rejoins The Sun.
M. Fulcher ‘Believe Me’ in Afro-American (Baltimore, MD) 3 Nov. 10/3: The new edition of ‘Shuffle Along’ [...] has the main stemmers with hardened mitts because of applause.

In phrases

buzz the main stem (v.) (also mooch the main stem, work the main stem)

to beg along a town’s main street.

[US]P. & T. Casey Gay-cat 301: Buzz, or mooch, or work the main drag or stem—to beg or bum along the main street.
on the stem

(US tramp) walking the main street of a town, begging for subsistence.

[US]N. Anderson Hobo 54: These clothes are usually solicited from the public, and the men on the ‘stem’ believe that they are entitled to them.
[US]G.H. Mullin Adventures of a Scholar Tramp 236: One old floater had said to me, ‘Kid, you kin get yer three squares a day, booze, and lots o’ jack on the stem.’.
[US]C. Himes ‘Every Opportunity’ in Coll. Stories (1990) 247: Ted said he wasn’t on the stem and Tony looked relieved.
[US]N. Algren Never Come Morning (1988) 207: She asked him for a quarter for luck, but he only looked dour and muttered something about being on the stem himself.
[US]Goldin et al. DAUL 209/2: Stem, on the. 1. On the main street of a town or village; on the highway. 2. Engaged in, or by means of, panhandling.
[US]I.L. Allen City in Sl. (1995) 41: The phrase on the stem is hobo jargon for walking the main street of a town, sometimes panhandling and begging.