An ear of maize or sweetcorn suitable for cooking, especially by roasting. Also in "to be in roasting ear": (of maize) to be ripe for harvest; to be suitable for cooking.
Origin
Mid 17th century. From roasting + ear.
Definition of roasting ear in US English:
roasting ear
nounˈrəʊstɪŋ ˌɪə
US
An ear of maize or sweetcorn suitable for cooking, especially by roasting. Also in "to be in roasting ear": (of maize) to be ripe for harvest; to be suitable for cooking.