stain

B2 · Upper Intermediate Countable noun Science Technical

n. a liquid used to colour wood or to make tiny things visible under a microscope.

n. a substance used to penetrate a surface for colouring, or a reagent used to highlight structures in microscopic specimens.

“We chose a dark oak stain for the new kitchen floor.”

“The lab technician applied a fluorescent stain to the tissue sample to make the cellular nuclei clearly visible under the microscope.”

C1 · Advanced Countable noun Literary · Formal

n. something that makes people think less of a person's character or name.

n. a metaphorical blemish or taint on a person's reputation or moral character.

“The scandal was a permanent stain on the politician's career.”

“The false accusations remained a stain on his professional integrity long after he had been officially cleared of any wrongdoing.”

B1 · Intermediate

v. to leave a mark on something that is hard to clean.

v. to discolour a surface through contact with a substance; can be used transitively or intransitively.

“Be careful with those berries because the juice will stain your fingers.”

“The spilled ink quickly soaked into the porous wooden desk, staining the surface permanently before anyone could find a cloth.”

B2 · Upper Intermediate Cooking

v. to change the colour of something, like wood, using a special liquid.

v. to treat a surface with a pigment or dye that penetrates the material rather than sitting on top.

“He decided to stain the fence dark green to match the garden gate.”

“The carpenter stained the mahogany panels to enhance the natural grain before applying the final protective wax.”