(forestry) A blue or grey discolouration in sapwood caused by mildew infection.

plural of blue stain

plural of blue slip

(US politics) In the House of Representatives, a rejection slip given to tax and spending bills sent to it by the Senate that did not originate in the House, per the House's interpretation of the Origination Clause.

A greenish blue pigment / colour

(organic chemistry) The phenothiazine dye 3-N,3-N,7-N,7-N-tetramethyl-10H-phenothiazine-3,7-diamine

plural of blue blossom

Alternative form of blueblossom

Any of a class of blue dyes that are related to the methyl violet dyes but contain one naphthylamino group.

(UK, slang, obsolete) The refuse ammoniacal lime from gas factories.