To sacralise something means to make it sacred or holy, like a religious ceremony or a special place.
Sacralising something is usually a very serious and important thing in a religion or culture.
Examples:
The priest will sacralise the new church.
People sacralise the river by throwing flowers into it.
In some cultures, they sacralise certain animals.
She sacralised her favorite tree by decorating it with ribbons.
The ancient people sacralised the mountain by building a temple on its top.
He sacralised the old book by placing it on a special shelf.