The best Greek Dictionary is at www.STEPBible.org

The Liddel-Scott-Jones (LSJ) lexicon is the best dictionary for ancient Greek. It covers the whole of ancient Greek literature - not just Bible Greek - so it can show us what the original readers thought when they read the NT or the LXX (the Septuagint translation of the OT into Greek from the 2nd century BC).

STEPBible.org already had a cut-down version of LSJ but now it has the full entries - and more. The STEP version is much easier to use than the paper one. First, of course, you don't need to find the entry - youjust click on a word or typing the English meaning. Looking up an entry in the paper version can be harder than you'd think because spelling varied a great deal. Some sounds such as 'r' and 'l' were often spelled differently because ancient Greeks (like Chinese) couldn't always hear the difference. 

The STEP version of LSJ is also much easier to read than the original or other electronic editions. It uses bold for definitions, italics for gramatical terms and hides bibliographic data under the date links. These dates indicate the earliest cited evidence for each meaning, so you can trace the development of the word.

Also, the arcane abbreviations have been unpacked. So, for example:
* "dat. pers. et rei" in the STEP LSJ is "dative of persons and of things",
* "A. Ag." in the STEP LSJ is: "4th-5th c.BC: Aeschylus Tragicus 'Agamemnon'"
* "sc."  in the STEP LSJ is replaced by "i.e.".

(Compare this with the photo of the printed page above)

Now we can find answers to quesions like:
Why did Saul change his name to Paul? Surely he wasn't ashamed to be named after a Jewish king? Most Greek dictionaries don't help us, but LSJ can tell us the answer because it covers everyday Greek, and not just religious Greek. The word saulos (the Greek version of Saul) means "a sexual thrust", so you can imagine the sniggers whenever he was introduced. It is possible that 'Saulos' was his cognomen (his Roman nickname or familiar name) while  'Paulos' was his prenomen (a formal forename) because we do know of four families that used this unusual prenomen (my thanks to Irina Levinskya who dug this up for me). He must have been relieved to find another name that was more acceptable in Gentile society.

A great deal of checking has been done at Tyndale House. Greek dictionaries often fall down over the accents, which can be surprisingly important. For example, kalós means 'good' but kálos means 'rope'. To a Greek this is equivalent to the different words in "I resume writing my résumé".

All software has mistakes (as we've found while using them to check STEPBible) so do please tell us if you find any errors. And all editions of LSJ also have errors. For example, the Logos version dates psudonemous authors as if they were the real person they are impersonating. So Pseudo-Plutarch's work on the life of Homer (written by a pretender in the 3rd or 4th C AD) is dated in the 1st C AD - a key period for NT Greek. (I'm only reporting this minor glitch in order to prove that Tyndale House scholars have examined these things in detail).

Actually, the edition of LSJ sold by Logos is the best one I've seen, based on the error-checking we did. Logos even provides a free version of Perseus which works really well with their LSJ. The version at Tufts  is also very good because it has lots of corrections and it links to most of the original sources (though you can only view a few of these on the free version). The LSJ at Perseus is great because, although it has fewer links and corrections, the sources are mostly available in English as well as Greek - and because they made their version of electronic LSJ available on a public licence. The fast Chicago LSJ is based on Perseus, like most free software including STEPBible.

The STEP version has benefitted from all of these and it has a unique added feature: dates which help to plot which meanings applied when the LXX and NT were written. We will make it available on a public licence when we have finished tweeking it, so other software will benefit from this. So have a go and spread the news.