per·o·no·spo·ra·ce·ae \ˌperənōspəˈrāsēˌē\noun plural Usage: capitalized Etymology: New Latin Peronospora, type genus + -aceae : a family of parasitic fungi (order Peronosporales) in which the conidiophores form outside the epidermis of the host and develop conidia or sporangia singly or in clusters but never in chains — see downy mildew • per·o·no·spo·ra·ceous\| ̷ ̷ ̷ ̷ ̷ ̷ ̷ ̷|rāshəs\adjective