nYardland(O. Eng. Law) A measure of land of uncertain quantity, varying from fifteen to forty acres; a virgate.
Century Dictionary and Cyclopedia
nyardlandThe area of land held by a tenant in villeinage in early English manors, consisting usually of an aggregate of some 30 strips in the open fields with a messuage in the village. In some counties it was 15 acres; in others 20 or 24, and even 40 acres. See holding, 3 . Also yard of land.
One would have to suppose that most fields were divided into two parts, as the majority of the tenements are yardlands with half a team.