There have been many references to different Esperanto dictionaries here such as LaTex, ReVo, etc. I would like to understand the origin of these and why people rely on one more than the other. Is there a general consensus as to which is better? Is one better for one type of vocabulary than another? Basically, I'd like to understand the differences- strengths and weaknesses of each summarized.
I believe the two main dictionaries for definitions in Esperanto are PIV and ReVo.
PIV is the Plena Ilustrita Vortaro de Esperanto. Traditionally it is sold as a very large book but recently its contents can be found online at vortaro.net. It is created by SAT and is generally considered an authoritative source on Esperanto vocabulary. Restricting yourself to only words and usages that appear in PIV is generally a good way to avoid controversy in an Esperanto text.
ReVo on the other hand is a collaborative project that can be edited by almost anyone much like Wikipedia. Unlike PIV, the content is freely usable under the GPL license. It was originally based on a very early version of the Plena Vortaro which fell out of copyright, but it has since diverged quite a lot. Due to how it is edited, it tends to be more up-to-date than PIV and more often describes how the language is actually used rather than trying to dictate correct usage. For example, it has articles on neologisms such as ri and iĉ. It is also the source of data for the PReVo and Praktika Vortaro applications. Additionally, it includes translations into many other languages. These can be very useful but it is missing a lot of words and sometimes the translations are misleading.
You might argue that a wiki-style dictionary would be less reliable than PIV, but in practice personally I find ReVo to be a very useful source. Because of it being digital-only, there is a lot more room for detailed definitions and often there are long “remarks” which give very good advice on how the word is used.
There is a highly respected dictionary for translation to and from English by John Wells. However, of course, bilingual dictionaries are more useful as a learning aid rather than being an authoritative source on the meaning of a word.
As far as I know, LaTex is not a dictionary, rather it is an unrelated piece of software for typesetting documents.
To Neil Roberts’s excellent list I’d like to add Wiktionary, both the Esperanto one, and the English one, which has a surprising amount of Esperanto definitions, for example mojosa. Sometimes, Wiktionary is the only way to find a contested word, such as the rare neologism knufli (not in ReVo). (Of course, like ReVo, W. is a collaborative effort, so use it with care.)