Greetings Marg, welcome to LawnSite.
This site is probably the best source for all the info you're looking for. Suggest using the search function. Type in one term, abbreviation, phrase, etc at a time. You'll find threads/discussions/posts about each. May have to do some analytical reading to solve the actual definition for each, but you'll get an education here for free.
If there's any you can't figure out, start a thread with one type of 'term' and just ask what is this/what does this mean, type question.
Equipment dealers themselves are another good source for this type of info, just remember, they are sales types.