Foam formed by water and a fluorocarbon surfactant, used in firefighting because it floats on flammable liquids lighter than water.
Water in its standard form of H₂O, containing two protium hydrogen atoms, as opposed to heavy water.
A liquid that has been percolated.
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.