BEM names intentionally use double underscores and double hyphens instead of single to separate Block-Element-Modifier. The reason is so that single hyphens can be used as word separators. Class names should be very readable, so abbreviation isn’t always desirable unless the abbreviations are universally recognizable.
<!-- 👍 DO THIS -->
<div class="some-thesis some-thesis--fast-read">
<div class="some-thesis__some-element"></div>
</div>
<!-- 👎 DON'T DO THIS -->
<div class="somethesis somethesis--fastread">
<div class="somethesis__someelement"></div>
</div>