say-so n [Orig a brand name (see quot 1905) used into the 1920s; the generic use appar originated with LaFr speakers, for whom its status was less obvious, and was thence borrowed into local English.]
An ice-cream cone.
[1905 Janesville Daily Gaz. (WI) 28 Aug 5/4, Eddington and Fathers are visiting various fairs in southern Wisconsin and northern Illinois, manufacturing and selling Sayso ice cream cones. 1931 Read LA French 116, Say-so. . . English “say so,” used in various ways. Un say-so de crème, for example, is the equivalent of “a cone of ice-cream.” 1939 AmSp 14.200 sLA, The following English words have passed into the active French vocabulary with pronunciations approximately English. . . Say so [seso]. An ice-cream cone.] 1967 DARE FW Addit LA14, A say-so [ˈseɪˌsoᴜ]—old-fashioned—for ice-cream cone. 1981 DARE File seTX (as of c1930), As a child growing up in the Gulf Coast region near the Louisiana border I frequently went to the local drugstores to purchase a “say-so” (I never knew how it was spelled) which was an ice-cream cone. I have always suspected it was of Cajun origin.