vacuum in Wingdings is ❖︎♋︎♍︎◆︎◆︎❍︎

A space entirely devoid of matter (called also, by way ofdistinction, absolute vacuum); hence, in a more general sense, aspace, as the interior of a closed vessel, which has been exhaustedto a high or the highest degree by an air pump or other artificialmeans; as, water boils at a reduced temperature in a vacuum.