user13439: I've bought this microSD reader/writer: http://www.ebay.com/itm/131132034753
I've found only one tutorial, where the pins are similar to my pins, but in the example there is a CLK instead of SCK: https://learn.sparkfun.com/tutorials/microsd-shield-and-sd-breakout-hookup-guide
The pins on my MicroSD reader are:

CS
SCK
MOSI
MISO
VCC
GND


user41029: It's common practice for speakers/writers to use the generic term: "clock" (CLK) for various different situations. This clearly being a serial interface we don't need to specifically say Serial cloCK each time the signal mentioned, as it's more of a mouthful than saying "clock".  
In this case consider "CLK" and "SCK" as fully interchangeable.  

user4143: SCK stands for SPI ClocK
CLK stands for SPI CLocK
Two different acronyms for the same thing.

13439: <p>I've bought this microSD reader/writer: <a href="http://www.ebay.com/itm/131132034753" rel="nofollow">http://www.ebay.com/itm/131132034753</a></p>

<p>I've found only one tutorial, where the pins are similar to my pins, but in the example there is a CLK instead of SCK: <a href="https://learn.sparkfun.com/tutorials/microsd-shield-and-sd-breakout-hookup-guide" rel="nofollow">https://learn.sparkfun.com/tutorials/microsd-shield-and-sd-breakout-hookup-guide</a></p>

<p>The pins on my MicroSD reader are:</p>

<ul>
<li>CS</li>
<li>SCK</li>
<li>MOSI</li>
<li>MISO</li>
<li>VCC</li>
<li>GND</li>
</ul>
 41029: <p>It's common practice for speakers/writers to use the generic term: "clock" (CLK) for various different situations. This clearly being a <em>serial</em> interface we don't need to specifically say <strong>S</strong>erial clo<strong>CK</strong> each time the signal mentioned, as it's more of a mouthful than saying "clock".  </p>

<p>In this case consider "CLK" and "SCK" as fully interchangeable.  </p>
 4143: <p>SCK stands for <strong>S</strong>PI <strong>C</strong>loc<strong>K</strong></p>

<p>CLK stands for SPI <strong>CL</strong>oc<strong>K</strong></p>

<p>Two different acronyms for the same thing.</p>
