http://www.amazon.co.uk/Chambers-Dictionary-Science-Technology-available/dp/0550130020/ref=sr_1_1?ie=UTF8&qid=1372238631&sr=8-1&keywords=chambers+dictionary+of+science+and+technology
For editing Science and Technology, you need a few good specialist dictionaries. Chambers Dictionary of Science and Technology was recommended when I first started, although it took me a whle to buy, as it often seems to be out of print. It is, however, very comprehensive, and has clear explanations.