Of a fluid: to become more viscous.
To thicken a fluid, in the sense of making it more viscous, especially by boiling, evaporation, or condensation; to condense.
To pass a liquid through a porous substance; to filter.
To make (coffee) in a percolator.
To drain or seep through a porous substance.
To spread slowly or gradually; to slowly become noticed or realised.
A liquid that has been percolated.