Empty space with nothing in it. Also to make null — the same word for an absence and for the act of creating one.
Old French voide, from Latin vocivus/vacuus (empty), related to vacare (to be empty), named an absence and, as a verb, the act of making one.
The sandbox realm, where an idea is tested before it touches a realm proper and is purged once it no longer serves. Empty space with nothing in it, and, as a verb, the act of making something null, the same absence the realm's own purge enacts.