A lightweight board having an upper covering layer, which extends in a longitudinal direction, a lower covering layer, which extends parallel to the upper covering layer and is spaced apart from the upper covering layer in a direction perpendicular to the longitudinal direction, a light middle layer, which extends between the upper covering layer and the lower covering layer, and a bar, which extends between the upper covering layer and the lower covering layer and consists of wood or wood-based material. To simplify the production of a connection arrangement, the bar has a machine-worked tongue profile and/or groove profile, which is formed for mechanical locking in the longitudinal direction and in the direction perpendicular to the longitudinal direction with a corresponding profile of a further component. The invention also relates to a corresponding connection arrangement and a corresponding method for producing a connection arrangement.