Green’s Dictionary of Slang

maryjanes n.

[the schoolgirl sound of the proper name]

(orig. US) round-toed shoes with a strap across the foot.

[US]Keowee Courier (Pickens Court Ho., SC) 17 May 5/2: [advt] Ladies Mary Jane Pumps ...$1.18.
[US]Frank Sinatra [on-stage at Las Vegas] My maryjane’s been bitin’ me for the past few minutes ... this one’s bitin’ my instep.
[Can]M. Atwood Cat’s Eye (1989) 113: Plaid was the fashion in my day too. The white socks, the Mary Janes.
[UK]The Guardian 7 June: Heaven forbid that Runga should get too big for her boots (actually little black Mary Janes by the Milan designers Costume National).