[TartanJack]

I was looking at some suspension parts and noticed that the descriptions for the non-spring or sway part of the interchangable suspension parts is sometimes described as a shock and sometimes as a strut.
I know those terms often get used interchangeable but they are not the same thing.
The internal designs work different and they are used somewhat differently in a suspension design.  Suspensions are designed for shocks or struts and they are NOT interchangeable with one another.
"Strut"-> http://en.wikipedia.org/wiki/MacPherson_strut
Also, the design of the upper part of a strut is what makes a Strut Bar actually effective.
http://en.wikipedia.org/wiki/Strut_bar
For contrast:
Shock-> actually short for "Shock Absorber"-> http://en.wikipedia.org/wiki/Shock_absorber
(Wiki used as it provides accurate enough descriptions that are easy to understand and good illustrations.)

I am only aware of this b/c the Miata uses shocks and NOT struts, so a buyer needs to be careful which they get, esp. if buying from a non-Miata parts dealer.

Most cars today use struts, inc. the BMW Z-3 (note that its struts are often listed as a disadvantage compared to the contemporary Mazda soft-top.
I am assuming that they are struts and NOT really shocks and the word usage is from present mis-use of the word shocks to include struts, as they look alike and are used in the same part of suspension system.

So, which do we use?

Edit:
OR am I wrong in my understanding and a strut actually IS a type of shock . . . ?

 

[Sparks_Scion_TRD_Parts]

According to Toyota's Electronic Parts Catalog, the fronts and rears are both called shock absorbers.

Ken

 

[TartanJack]

Thanks Ken.

I might be using an outdated understanding of the terms as well.
The line of demarcation I am thinking of may or may not exist.

 

[TRDSPARKS]

Now they use the term loosely. A strut does the same exact thing as a shock only difference is how the springs are mounted. A shock is separate from the springs where the strut is attached to the springs. Thats the only difference I see, basic functionality is the same though.

 

[Maytag]

We run struts up front.

Ken's right though. The big difference is that the strut acts as the bottom mount of the coil spring. Whereas regular shocks, generally do no support of vehicle weight, and solely absorb bumps and roadway irregularities.

Some front strut setups also consist of some steering components also.

I looked at the xB's front struts, and they are also connected to the ends of the front sway bar. This is another feature that may be found on front strut suspensions.

 

[TartanJack]

Look and you shall find . . .

Looking at the downloadable instructions on the Sparks site for the TRD springs, it labels the suspension parts.
Low and behold, they are SPECIFICALLY termed.
http://www.trdsparks.com/displayparts.php?Mdl_dtl=570&Part_cat=11&parts_id=1565
So:
The fronts are struts and the rears are shocks.
That answers my question!

For that answer, I would like to give a public kudos to Sparks for providing those!
They not only allow one to know what it entailed in installing what they are buying (a HUGE benefit and their primary purpose), but they are also helpful in knowing what related parts are there and provide some useful info on them for those without access to the parts diagrams and/or shop manual.
THANKS for providing them.  They helped me in answering this question!