1. How vocab is tested today
ACT vocab
How vocab is tested today

2. How Vocabulary is Tested on the ACT
So today's tests are more complex than the one above from 1926; they try to test your understanding not only of the textbook definition of the word, but your understanding of its place in the language as well.
So it turns out that a word's use in the context of language is just as important as its definition. 
The ACT takes an even subtler approach to testing vocabulary: they include it where knowing the word is crucial to understanding or answering the question, usually without testing it directly. In other words, the vocabulary words on the ACT are usually surrounded by a decent number of hints as to their meanings. These hints are also known as context clues, and we'll talk about those next.

3. The ACT Loves Context
As we discussed earlier, knowing definitions of words isn't as good a measure of language mastery as is the skill of choosing the best word for a specific context. 
In other words, it's less about the words themselves and more about how they fit with the words around them. 
The ACT really takes this to heart and rewards students who know how to use context clues. By contrast, the SAT specifically tries to isolate words so that context gives limited help. Here's an SAT example

4. Context examples cir·cum·scribe ˈsərkəmˌskrīb/ verb
past tense: circumscribed; past participle: circumscribed
1. 
restrict (something) within limits.
"their movements were strictly monitored and circumscribed"
2. 
GEOMETRY
draw (a figure) around another, touching it at points but not cutting it.

5. Content examples to·tal ˈtōdl/ adjective
Comprising the whole number or amount
"a total cost of $4,000"
sound2
adjective
adjective: sound; comparative adjective: sounder; superlative adjective: soundest
1. in good condition; not damaged, injured, or diseased.
"they returned safe and sound"
com·plete
adjective
1. 
having all the necessary or appropriate parts.
"a complete list of courses offered by the college

6. Context example em·phat·ic as·sert adjective verb 1.
1. 
showing or giving emphasis; expressing something forcibly and clearly.
"the children were emphatic that they would like to repeat the experience"
as·sert
verb
state a fact or belief confidently and forcefully.
"the company asserts that the cuts will not affect development

7. What Kinds of Words the ACT Tests

8. The ACT Only Tests Medium-Level Vocabulary, but Tests It in Detail
When you look at ACT Words, you may already know many of the words. That's great!
But make sure you really do know what they mean—look them up and read them in a few different sentences to be sure.
Because while the ACT doesn't test you on SAT-style vocabulary like abstemious, crepuscular, or blunderbuss, it does test you on the nuances of its easier words, like adhere, cumbersome, and diffuse.
Many of these nuances include multiple meanings, which we'll delve into now.

9. The ACT Loves Words with Multiple Meanings
The ACT likes to test the secondary (less well known) or academic meanings of ­­words. Let's look at a few examples from real ACTs: what do the words determined and critical mean to you?
You probably thought of the most common definitions of these words: determined is an adjective that means "persistent," and critical is an adjective that means "disapproving."
But both of these words also have secondary, more academic meanings. Determined, for example, is also the past tense of the verb determine, which means "to establish something exactly." For example: "In the 16th century, Nicolaus Copernicus determined that the Earth revolves around the Sun." Determine, used in this way, is one of the most common vocabulary words on the ACT.
Critical, by contrast, is always an adjective (most words ending in "-al" are), but it still has multiple meanings. While the more popular meaning of critical, "disapproving," describes a person, the academic meaning describes an analysis or explanation of something. For example: "The scholar's critical analysis of Macbeth shows that Macbeth's greed is the main cause of the play's events.

10. The ACT Loves Idioms
Another way the ACT tries to test language skills (that the SAT does not) is idioms (phrases that mean something different than what the actual words mean). For example, "bite the bullet" is an English idiom that means to do something that's difficult to do. It doesn't have anything to do with biting or bullets. Here are a few idioms from recent ACTs:
hush-hush: secret
under wraps: secret
streak past: go past quickly
came about: happened
in the midst: during
sheds light on: reveals, explains
ill at ease: uncomfortable (mentally, not physically)
dwell on: focus on for longer than necessary
against the clock: under time pressure
stumbled upon: discovered by accident

11. More idioms
It's difficult to study idioms, and there are thousands of them in English. The ACT only tests idioms that are very widely used, so an easy way to improve your idiom knowledge is to read, read, read—anything that's not for kids.
I also have more explanations of idioms as well as a longer list available on my website.

12. The ACT Includes Science Vocabulary
Lots of people freak out about ACT Science, but it's really quite straightforward—if you're familiar with science. There are difficult topics and vocabulary, like heritable traits and conductivity, but the test explains all of these very specifically.
The more general and vague science terms, however, you have to already know or work around. One thing that can make ACT Science less scary (especially if you haven't taken chemistry or biology recently) is to make sure you know some basic scientific ACT vocabulary words.
The vocabulary list of “top 150 ACT words” that I have on my website, includes almost 40 science vocabulary words for just this purpose. It can also be useful to read articles in scientific publications, like Popular Science or the science section of the New York Times.

13. Carlisle assignment Go to my website under Test prep assignments
Complete the assignment entitled “ACT Vocab”
Once complete, use the “ACT Vocab answer guide” to self assess
Send me your score as well as a brief explanation of how well you did and what plan you have to improve (if need be) your ACT vocab knowledge