Definition of leach in English:



  • 1(with reference to a soluble chemical or mineral) drain away from soil, ash, or similar material by the action of percolating liquid, especially rainwater.

    with object ‘the nutrient is quickly leached away’
    no object ‘pesticides that leach into rivers’
    • ‘Polyurethane is a fully reacted polymer in which every molecule bonds with another so it is chemically inert, which keeps it from oxidizing or leaching chemicals, theoretically extending tire life.’
    • ‘This, combined with nutrients being leached out of the soils by high rainfall, may cause weakness in some plants and nutrient deficiency, particularly in sandy soils.’
    • ‘The pad is used to store a mound of ore through which chemicals percolate to leach out the gold ore, which is then collected and processed into bullion.’
    • ‘#6 Polystyrene can leach styrene, a possible human carcinogen that may also interfere with hormones.’
    • ‘He concluded that the pseudomorphs were derived when rainwater penetrating the near-surface layers leached out the sodium carbonate from the original shortite, leaving behind calcium carbonate.’
    • ‘The sort of feed may have to change, because the wetter winters will probably result in nutrients being leached out of the soil at a faster rate.’
    • ‘The other attraction of these materials, which were developed in the 1970s, is that they continuously leach fluoride and so can help reduce the incidence of recurrent caries.’
    • ‘If rainfall or irrigation is excessive, nitrate will be leached below the plant?’
    • ‘Humus being highly colloidal, has the ability to adsorb and retain for future plant use many of the ions such as calcium, magnesium, potassium, phosphates and ammonia which might be leached from the soil and lost in drainage.’
    • ‘When they looked at the data from their 1995-2001 study and saw how much nitrate was being leached from the soil, they realized just how important it is to manage drainage systems carefully.’
    • ‘The small chloride ion can also sometimes work its way past protective coatings and leach out soluble iron chloride salts, exposing new surfaces for attack.’
    • ‘It will stop rain leaching nutrients from the soil over the winter, and as it rots down it will improve the soil's texture and fertility quite naturally.’
    • ‘The key, once you've cleared a patch of ground, is to get something sown or planted to fill the vacuum: otherwise the winter wet will leach nutrients from the soil, and the weeds will undo your good work in a matter of weeks.’
    • ‘Soluble minerals are leached from soils on upper slopes, move down the slope, and are often deposited at the foot of the slope.’
    • ‘One drawback of organic-based products is the tendency of chemicals to leach from the matrix material, leaving parts of the surface unprotected.’
    • ‘Precious metals, such as platinum and gold, which may be present on the PCB, can also be leached and recovered electrochemically and reused.’
    • ‘Brackish and ocean waters may contain large quantities of sodium chloride as well as many other soluble compounds leached from the crust of the earth.’
    • ‘More recently they have speculated that acid rain robs trees of this vital nutrient by leaching it from the soil and by mobilizing aluminum, which interferes with calcium uptake by roots.’
    • ‘In the processes generally known as bioleaching, stress-hardy bacteria, which can get all their nutrient requirements from the air and the minerals to be leached, are typically employed to oxidise ores to a more soluble state.’
    • ‘In Australia, Mangareva, parts of the U.S. Southwest, and many other locations, most of the nutrients had already been leached out of the soil by rainfall.’
    drain, filter, percolate, filtrate, discharge, strain, leak, separate
    View synonyms
    1. 1.1with object Subject (soil, ash, etc.) to a leaching process.
      • ‘Millions of people in the Himalayas and Andes suffer from goitre and cretinism as glaciation, heavy rainfall and melting snow regularly leach mountain soils of their iodine content.’
      • ‘Both field evidence and binocular microscope inspection of the sediment from East Avenue Range indicate that the sediment is highly leached.’


Old English leccan ‘to water’, of West Germanic origin. The current sense dates from the mid 19th century.