Green’s Dictionary of Slang

ivory float n.

[rhy. sl.]

(US) a coat.

[US]M.C. Sharpe Chicago May: Her Story in Hamilton (1952) 132: Ivory float – coat.
[US]A.J. Pollock Und. Speaks.
[US]Monteleone Criminal Sl. (rev. edn) 87: float A coat.
[US]Berrey & Van den Bark Amer. Thes. Sl. (2nd edn).