A substance which, on first exposure, causes little or no reaction in man or test animals, but which, with repeated exposure, may cause a marked response not necessarily limited to the contact site. Skin sensitization is the most common form .
The esteem an individual holds for objects because of their history or emotional significance, unrelated their monetary value or replacement cost:
A toxic condition resulting from the spread of bacteria or their toxins from the point of infection to surfaces from which others may contract them.
An invasion of the bloodstream by virulent micro organisms from a local point of infection. Blood poisoning.
The waste and waste water produced by residential and commercial establishments and discharged into sewers.
A channel or conduit that carries waste water and storm water runoff (generally from more than one building) from the source to a treatment plant or receiving stream.
A gradual colour change across a surface: in plush carpeting and velvet fabrics, a non-uniform appearance caused by the varying reflectance of irregular pile lay.
A thick hand-split shingle formed by splitting a short log into tapered sections. Also a crack occurring in timber.
A resin coating originating in the secretions of insects, which are dissolved in alcohol or a similar solvent.
A thin piece of wood, metal, or stone, tapered so as to adjust the alignment of one surface to bring it flush with another.