These verbs express the action of passing into and spreading through every part of something, like a liquid or a gas. Permeate focuses directly on this concept. It emphasizes both entry and diffusion, indicating infiltration through the very pores. It may be used in a physical sense: a waterproof fabric, treated with a substance that keeps water from permeating it; spring rains that permeate the earth. Or it may apply to a sense impression: Cooking odours permeated the air. It is especially expressive in purely figurative contexts, with reference to intangibles.

• The atmosphere of England permeates the club; The spirit of his times permeates his writing; A sense of peace and contentment permeated the room, seeming to fill every nook and cranny.

Penetrate comes from a Latin verb meaning to put within. More strongly than permeate , it stresses the initial entry into something, and often implies the overcoming of resistance.

• A powerful headlight beam was needed to penetrate the fog; Here no sound can penetrate ; Penetrating cold went through his coat and chilled him to the bone; tissues that allow certain liquids to penetrate while preventing the passage of others.

Penetrate is also used of a figurative breakthrough, and may sometimes refer to a deep or lasting effect made on the mind or emotions: a psychiatrist using hypnosis to penetrate a patient’s amnesia; an attempt to penetrate the boy’s protective hostility.

Pervade comes from Latin roots meaning to go through; it marks a change in emphasis from entry to effect. Where permeate refers to an action like that of a gas which diffuses through all the pores or intermolecular spaces of a solid or another gas, pervade describes the action of a gas which fills all the open space of a chamber. Hence a gas pervades a room by permeating the air in the room. In extended senses, pervade is more closely synonymous with permeate ; it may be used throughout a thing.

• The headmaster’s influence pervades the school; a strange stillness pervaded the garden, like the hush before a storm; In the eyes of the priest, God seemed to pervade all creation.

Impregnate goes beyond permeate and pervade . It stresses the new qualities or characteristics gained by a substance through which some other substance has been diffused: air impregnated with poisonous gases. It is also used figuratively: Every page of his work is impregnated with his prejudices.

Saturate comes from a Latin verb meaning to fill up, and supersaturate is an intensification of it. In chemistry, a solution is said to be saturated when the solvent can hold no more of the solute under existing conditions of temperature and pressure: water saturated with salt. A supersaturated solution is one carried beyond the normal degree of saturation , made to hold more solute by a mechanical process of heating and cooling. A slight jar or the addition of one more bit of solute to such a solution can suddenly produce crystals. When air becomes saturated with water vapour, having a relative humidity of 100%, the excess vapour begins to condense as dew; when supersaturated , the air contains an amount of moisture more than sufficient to saturate it, as in a fog. In general usage, saturate means to fill anything to the utmost extent of its capacity for absorbing or retaining. Going well beyond permeate , it often suggests a thorough soaking or a being thoroughly soaked.

• Moisture permeated the wall, leaving it damp; Rain saturated their clothes, leaving them sodden; A swamp is land so saturated with water as to be unfit for tillage.

Saturate is also used figuratively.

• His mind was saturated with facts after hours of studying for the exam; She saturated herself in the culture and customs of her adopted land.

Supersaturate also has extended uses, referring to more of anything than can be absorbed or accommodated: a supersaturated labour market.

Imbue comes from a Latin verb meaning to wet, soak or dye. In a physical sense, it suggests the imparting of a colour that soaks in deeply and saturates the whole: The dye permeated the cloth, imbuing it with a rich red. In a figurative sense, it means to fill or impregnate , as with emotions, ideals or other intangible qualities.

• She imbued her son with the principles for which his father fought; fighting men imbued with patriotism; a strangely sinister place, imbued and saturated with an atmosphere of evil.