to be set apart from ordinary use and brought into the sphere of the holy: to be holy, to make holy, to treat as holy
This verb gathers up everything that happens at the boundary between the common and the holy. At its root is a single idea: to remove a person, place, time, or object from everyday use and move it into the realm that belongs to God, who alone is holy in himself. Each sense below is one angle on that single movement.
The word looks in three directions. It can describe a thing simply being holy, already standing inside the sacred sphere, sometimes so charged that its holiness spreads to whatever it touches. It can describe the act of putting something there, consecrating or dedicating it so that it is now God's and no longer available for common use. And, with God himself as the subject, it describes God being shown to be holy or treated as holy, his set-apart greatness honored or vindicated before people. A reflexive use covers people preparing themselves for an encounter with that holiness.
Because holiness in the Bible is first a matter of belonging to God rather than of moral goodness, the verb covers altars and priests and sabbaths as readily as it covers people purifying themselves, and it even reaches the everyday picture of a field becoming forbidden because its crop is now off-limits. The thread running through all of it is separation unto God.