Anything that makes reading comprehension easier is fair game. The list includes not just general vocabulary, but also foods, places, people, fashions, animals, etc. Since ajvocab.com is intended for the "average Joe" there are certain terms we ignore/include:

• We skip most high school vocabulary words, but there is some overlap. In the next few months the plan is to release a list of "core vocab" words that are frequently encountered in literature; words which every English speaker should know—and many of these are high school vocabulary words.
• The 50 US states and major US cities are not covered.
• Common, modern, American idioms and slang are not covered.
• Major countries are not defined, it is assumed they are known. There are other resources if you need to brush up.
• Familiar city names, such as Stockholm and Liverpool, are often included because, although everyone knows that these cities are in Sweden and England respectively, they often do not know exactly where (actually Raphael Andres' awesome photo of Stockholm is reason enough to include the definition for that city).
• Vocabulary for British words, slang, idioms, and geography is extensively covered (we were both baffled when we first encountered the word sleeper as used in Tolstoy's Anna Karenina).
• Our vocabulary collections also cover some French, Latin, and occasionally other languages. Note that it was especially common in the eighteenth century for authors to pepper their novels with Latin and French—so it helps to know at least some.

As it sounds, it is a title that has a 'complete' vocabulary list. Although we do make an effort to include every vocabulary card for the titles listed as "comprehensive", we do have our limits. We may not, for instance, include some abstruse vocabulary word that is found only in a single instance and nowhere else. (Then again, we might. We're mercurial like that.)

If we claim a term is not used in a particular book, and that title is a comprehensive type, and it is used in the same sense as one of our definitions, then we missed one. Shoot us an email and if we concur, we'll fix it.

1. Many of the definitions are not finished; we complete and post them in the support order on the title list page.
2. Several of the definitions contain sound files and images from open sources, and many of these require licenses. Although we have dutifully included the license information where required, we would not be willing to gamble $30,000 that we made no errors. When we read that news item we removed over half of our content so we can verify the license information (this before site launch). If the “unintended consequences” from that dysnomy proves as bad as we think, we may shut the website down.

• apse is classified as both christiantity and architecture
• bêche-de-mer is classified both as zoology and culinary
• Blighty is classified as britain, slang, and geography

Complicating matters are words that have several meanings. One example is sorrel which has both an equestrian and an unrelated botany definition. In this case we made a separate definition for sorrel horse. When this is not possible we try to find at least one usage example for each definition. It is not the perfect solution, but for now it is the best we can offer.

As of today it will likely be Shakespeare's Hamlet since Shakespeare liked to coin new terms. We decided to make Ben Jonson's The Alchemist comprehensive as well just for comparison.

As a general rule older titles tend to have higher difficulty indices.

Roughly means that we are only partway finished with our vocabulary collection; the value is calculated by extrapolation. For example, as of today our Hamlet vocabulary collection contains 202 words. Had we no more terms to add at this point the difficulty index would be:

About implies the collection is at least 90% complete. The difficulty index in these cases likely won't drop, but the value might inch up somewhat.

Quite simply it is the total number of vocabulary words in a book divided by how many thousands of words in that book. So the difficulty index for a 100,000 word book having a vocabulary count of 100 equals exactly one.

Remember that our difficulty index IS NOT our rating of how good a book is; we have read many fantastic books that do not require extensive vocabularies (Jane Harper's The Dry is one example, Fannie Flagg's Fried Green Tomatoes is another). If people thought that the best books were only those with the most difficult words, they would only read books in languages they don't understand.

It only makes sense to calculate this index for titles we list as comprehensive, so we do not publish difficulty indices for partial (or other) types.

Are they commonly known? Likely the average Joe knows that Rembrandt was a Dutch painter, Mozart a composer, and Liverpool is in England. My bet is that they cannot differentiate between a Rembrandt and a Renoir, wouldn't know Mozart's music from Liszt's, and couldn't point out Liverpool on an unlabeled map. Even Hyacinth Bucket struggled with the first two (although it's assumed she knew were Liverpool is).

BTW, if you attempt to read Marcel Proust's novel In Search of Lost Time, knowing the artists and composers helps greatly with comprehension, regardless of which translation you read.

OK, we concede that sometimes we do go too far, but it really does help reading comprehension to have a good grasp of geography; it makes it easier to follow the plot.

• skipped:
  Bob failed to meet us because he is a heavy sleeper when he is soused.
• included:
  It would be meeter for Bob to eat souse on sleepers when trains are not coming.

The “uses” button is greyed-out when the word is not in that vocabulary collection. If we believe the word is in a selected book, then the “uses” button will have a black border. This makes it possible to click through different book titles on the side menu and quickly ascertain whether that vocabulary word is in that collection.

lassitude is not in our Anna Karenina vocabulary collection.

lassitude is used in Orwell's 1984.

Remember that we do not necessary show every vocabulary word use for every title, but if we claim a word is in a book, then it is probably in that book (or at least some form of that word).

It's just not practical, therefore we try to include at least a few and place the best uses towards the top.

As an example, take the word irresolute. Although we provided five uses of the word, we know that irresolute is also used in War and Peace, Wuthering Heights, Moby Dick, Uncle Tom's Cabin, Treasure Island, Frankenstein, The Adventures of Tom Sawyer, The Count of Monte-Cristo, Jane Eyre, Ulysses, and over a dozen other titles that we are aware of. This may be an extreme example as irresolute is (what we call) a core vocab word, but it illustrates the point.

We are working on it—and we need help. Unfortunately we lack the programming infrastructure for such sharing, but if we get enough feedback from people willing to help with word pronunciation we will write the code.

This would basically involve a (non-automated) new user screen, a record button, a playback button, an upload button, and some code infrastructure. It is doubtful we could support smartphones. As with all software, bug fixes and improvements would be incremental.

Shoot us an email on the contact page if you are willing to help with word pronunciations (also note languages and region). If there is enough interest we will write the code.

There are just a few criteria:

1. The external website must have a decent amount of searchable data; nobody likes to visit a site that constantly returns no results found. Even ajvocab.com fails this criteria, but we get a pass.

2. The site must respect people's privacy. Unfortunately very few websites meet this condition, and often when a site claims to respect privacy it's nugatory because the site utilizes one (or more) of those nearly ubiquitous web analytic tools; so every detail of your visit is tracked, recorded, and aggregated by a third party that could give a rat's ass about privacy. Here is a perfect example of this; three trackers on “we-are-committed-to-the privacy-of-our-visitors” noaa.org—blocked by duckduckgo's privacy essentials. (And why does a government-funded agency use these intrusive technologies? Maximize profits?)

   Had we been too strict with this policy there would be few links. Therefore we decided to take a more pragmatic approach: we give preference to sites with the best privacy practices and exclude those with the worst. The displayed icons are roughly ordered from left to right in order of best to worst privacy practices. This is not automatically calculated and must be occasionally reviewed.

   If you are unfamiliar with the intrusive tracking that seems to have become the core of the internet, we suggest that you install duckduckgo's privacy essentials and/or use the brave browser; both block trackers and give an indication of how much (or little) a website values privacy.

geography links, for example.

The icons on the vocabulary page change to reflect the category. So there are special sets of icons for, i.e. places, artists, birds, and music. Not every category has a special set of icons.

We are always looking for sites that offer good content and respect people's privacy, so before suggesting a site first make sure the website meets these basic criteria.

That was our original intent, however there are several considerations with wiki pages:

1. What happens when users upload copyrighted content? We are not lawyers, but we do know the copyright landscape is rapidly changing. We do not have time to fret over nor keep abreast of these changes. This 2019 copyright bill put the nail in the wiki-coffin as far as we are concerned; even if that gets defeated, similar (or worse) bills will pop up.
2. ajvocab.com is not a multi-million dollar, multi-thousand volunteer organization like wikipedia; we just do not have the resources.
3. We already use data from external wiki sources, seems redundant.
4. Ever looked under the hood (the talk link) on a wiki page? Sometimes those discussions can get quite heated. Wikipedia has the infrastructure to handle abuses, but again, we are not wikipedia nor do we aspire to become wikipedia.