Green’s Dictionary of Slang

anything to which one cannot give a name when required; also used euph.

1830		A.L. Campbell Tom Bowling I ii: He always sent him regular what-you-may-call-’ems, per-mittumces, till, within these last twelve months.
1834		in Bang-Up Songster 19: [song title] ‘The Squire’s Thingumbob and Kitty’s What You May Call It.’.
c.1864		Rakish Rhymer (1917) 83: [song title] ‘The Squire’s Thingumbob and Kitty’s What You May Call It’.
1881		J.C. Harris Uncle Remus 163: His wuds wuzent more’n cole ’fo’ wunner deze yer whatchyoumaycollums — wunner deze dentis’s mens — had retched fer it wid a par’r er tongs.
1889		C. Chesnutt ‘The Conjurer’s Revenge’ in Conjure Woman (1899) 120: De cunjuh man say his daddy wuz a king [...] er some sorter w’at-you-may-call-’em ’way ober yander in Affiky.
1898		Binstead & Wells Pink ’Un and Pelican 210: Sure enough, in the 2.30 race Lord (whatyermycallit) Lennix brings off a clean hundred an’ twenty.
1903		J. Furphy Such is Life 49: ‘Duffing soon comes under the what-you-may-call-him.’ ‘Statute of Limitations?’.
1910		‘O. Henry’ ‘A Night in New Arabia’ in Strictly Business (1915) 221: I’ll practice that what-you-may-call-it.
1912		E. Pugh Harry The Cockney 163: Though I ain’t done much o’ that what-you-might-call professionally.
1913		Sport (Adelaide) 30 Aug. 92/: They Say [...] That Dicky T [...] cut down his cadet overcoat to make his sister a pair of ‘what you may call its’.
1922		Joyce Ulysses 711: I went around to the whatyoucallit everything was whatyoucallit.
1935		W. Smith Bessie Cotter 51: ‘Too bad about Carrie,’ said Bessie. ‘Shot right in the whatcha-ma-call-it.’ Al grinned.
1940		R.L. Bellem ‘Death’s Passport’ in Goodstone Pulps (1970) 114/1: The sudden surge of her gorgeous whatchacallems under her fawn jersey frock.
1945		(con. 1900s) S. O’Casey Drums Under the Windows 143: The fact is there isn’t a single what-you-may-call-them from one end of holy Ireland to th’ other!
1950		C. Harris Three-Ha’Pence to the Angel 48: ‘What yer think this is, a exhibition, leaving your whatyermecallems about for everyone ter see?’ ‘My pants?’.
1951		(con. 1941) E. Lambert Twenty Thousand Thieves 43: Groggy’s a watchercallit — a figurehead.
1951		J.D. Salinger Catcher in the Rye (1958) 108: Want me to get his wallet? [...] It’s right on the wutchamacallit.
1959		S. Bellow Henderson The Rain King 29: You last husband went to President Roosevelt’s prep school – watchumajigger.
1960		N. Hilliard Maori Girl 168: I’m running a restaurant, not a call-house or whatyoucallit.
1960		P. Rabe Murder Me for Nickels (2004) 77: Please take off those watchamercallems.
1965		L. Bruce How to Talk Dirty 162: I can’t get my whatchamacallit, my oh-my, into my pants.
1977		E. Torres Q&A 54: We ain’t got no time for no jaywalkin’ whatchmacallit.
1983		J. Byrell (con. 1959) Up the Cross 160: ‘Let’s have one of those...whatchamacallits...schooners’.
1989		P. Slabolepszy ‘Smallholding’ in Mooi Street (1994) 208: King Dinga-malerie, man. Whatjoo-macallit . . .! Everything he touched turned to gold.
1989		C. Hiaasen Skin Tight 273: He’s the quack who gave her the encapsulated whatchamacallits.
1992		K. Lette Llama Parlour 44: Jest quit blabbin’ and fill in the whatchamacallit.
1997–2002		Hope College ‘Dict. of New Terms’ 🌐 whatchie n. A title referring to something, someplace, or someone that the speaker does not know the name of.
2000		B. Wiprud Sleep with the Fishes 74: There you have it [...] A whatchamacallit, a testimonial.
2000		W.T. Vollmann Royal Family 264: And you’re still holding a torch for Whatchamahoosis.
2004		C. Hiaasen Skinny Dip 202: How me come to — whatchacallit? — mastermine the blackmail.
2006		D. Mitchell Black Swan Green 363: She fixed you up with a whatchamagooey, a poultice, right?
2009		J. Stahl Pain Killers 26: He’s got the whatchamacallems, the shylocks, growing outta his temple.
2010		L. Redhead Thrill City [ebook] I’m not gonna kill ya [...] I don’t have the whatchamacallit? Facilities.
2021		P. Papathanasiou Stoning 83: [of a large kangaroo] ‘[T]his big red boomer bastard tore his whatchamacallit . . . oesophagus’.