Definitions, chemical structures, and other specifics are in dictionaries, encyclopedias, and handbooks, in print or online. These are examples--there are many more.

These act more like handbooks than 'dictionaries.' For example, the Dictionary of Organic Compounds lists chemical information and structures but also boiling points, polymerization points, explosiveness, and toxicity.

 These are just a select few of many available Web resources for agriculture.