Fred Schreiber's listing of the three dictionaries is similar to what I
was about to send. I would add only that if you wish to use a dictionary
for Renaissance usage (Vesalius, for example), the Cassell's dictionary is
particularly good as it gives the so-called transformed usages, which
match the Renaissance usage rather closely. I work a lot with 16th- and
17th-century astronomy, and for this it is very helpful to have an
18th-century copy of Ainsworth's Dictionary, which matches the use when
Latin was still a live language for international science.
OWEN GINGERICH