The Collaborative International Dictionary of English v.0.48:
Haver \Hav"er\, n. [D. haver; akin to G. haber.] The oat; oats. [Prov. Eng. & Scot.] [1913 Webster] Haver bread, oaten bread. Haver cake, oaten cake. --Piers Plowman. Haver grass, the wild oat. Haver meal, oatmeal. [1913 Webster]