stain

1a :  a soiled or discolored spotb :  a natural spot of color contrasting with the ground

2 :  a taint of guilt :  stigma

3 :  a preparation (as of dye or pigment) used in staining: such asa :  a dye or pigment capable of penetrating the pores of woodb :  a dye or mixture of dyes used in microscopy to make visible minute and transparent structures, to differentiate tissue elements, or to produce specific chemical reactions

1 :  to soil or discolor especially in spots

2 :  to use something (as a dye) to change the color of I spent the weekend staining the deck.

3 :  ¹corrupt 1 Her conscience was stained.

4 :  ¹disgrace The scandal stained his reputation.

1 :  ¹spot 2, discoloration Will this stain wash out?

2 :  a mark of guilt or disgrace :  stigma

3 :  something (as a dye) used in staining

1:  to cause discoloration of smoking stains teeth

2:  to color by processes affecting chemically or otherwise the material itself stain bacteria with a fluorescent dye

1:  a discolored spot or area (as on the skin or teeth)—see port-wine stain

2:  a preparation (as of dye or pigment) used in staining something; especially :  a dye or mixture of dyes used in microscopy to make minute and transparent structures visible, to differentiate tissue elements, or to produce specific chemical reactions