Subject-specific dictionaries are reference books that contain an alphabetical list of words with information about them that is specific to that particular subject and not necessarily generic like you would find in an average, everyday dictionary.
The Oxford English Dictionary (OED) is widely regarded as the accepted authority on the English language. It is an unsurpassed guide to the meaning, history, and pronunciation of 600,000 words— past and present—from across the English-speaking world.
The updated fourth edition of the Dictionary of Ecology is the most comprehensive and authoritative dictionary of ecology available. Written in a clear, accessible style, it contains more than 6,000 entries on all aspects of ecology and related environmental scientific disciplines such as biogeography, genetics, soil science, geomorphology, atmospheric science, and oceanography. The information covered in the dictionary is wide-ranging and includes plant and animal physiology, animal behavior, pollution, conservation, habitat management, population, evolution, environmental pollution, climatology and meteorology. It also features many line drawings and useful appendices including estimations of population parameters, the geologic time-scale, SI units, and--new to this edition--a web-linked appendix of relevant organizations including both governmental agencies and conservation societies. Fully revised, updated, and expanded, with over 100 new entries, this fourth edition also contains new web links for dozens of entries--which are accessed and kept up to date via the Dictionary of Ecology companion website.