Acid, a chemical name given to many sour substances.
Albumen, a nitrogenous organic compound.
Albuminoid, a nitrogenous substance resembling albumen.
Ammonia, a gas containing nitrogen produced by the decay of organic matter.
Annual, a plant that lives only one year; corn and sunflower are examples.
Anther, the part of a stamen that bears the pollen.
Available, that which can be used.
Bacteria, very small plants, so small that they cannot be seen without the aid of a powerful microscope. They are sometimes called "germs." Some of them are beneficial, some do great harm and some produce disease.
Biennial, a plant that lives two years, usually producing seeds the second year.
Bordeaux mixture, a mixture of copper sulphate, lime and water used to prevent plant diseases. It was invented in Bordeaux, France.