Definitions
1.NounA discolored spot or area caused by spillage or other contact with certain fluids or substances.
2.NounA blemish on one's character or reputation.
3.NounA substance used to soak into a surface and colour it.
4.NounA reagent or dye used to stain microscope specimens so as to make some structures visible.
5.NounOne of a number of non-standard tinctures used chiefly in post-medieval heraldry, especially tenné, murrey, or sanguine.
6.VerbTo discolor, as by spilling or other contact with a fluid or substance."to stain the hand with dye; armour stained with blood"
7.VerbTo taint or tarnish someone's character or reputation
8.VerbTo coat a surface with a stain"to stain wood with acids, coloured washes, paint rubbed in, etc.; the stained glass used for church windows"
9.VerbTo become stained; to take a stain.
10.VerbTo treat (a microscopic specimen) with a dye, especially one that dyes specific features
11.VerbTo cause to seem inferior or soiled by comparison.