How to use Bootstrap whilst maintaining semantic HTML markup?

Bootstrap provides mixins which you can use. So instead of adding classes like col-xs-12 in the HTML, you'd use @include make-xs-column(12) inside the selector block for the element. To add a row, there's the @mixin make-row.

Referring to an answer by Alexey Morashko, instead of this unsemantic markup:

<div class="items-list row">
    <div class="item col-xs-12 col-sm-6 col-md-4">
        <div class="item-name">Product first</div>
        <div class="item-description">Lorem ipsum dolor sit amet, consectetur adipisicing elit.</div>
    </div>
    <div class="item col-xs-12 col-sm-6 col-md-4">
        <div class="item-name">Product second</div>
        <div class="item-description">Ratione, ullam, reprehenderit aliquid saepe ab harum.</div>
    </div>
    <div class="item col-xs-12 col-sm-6 col-md-4">
        <div class="item-name">Product third</div>
        <div class="item-description"> totam repudiandae velit eum accusantium veritatis.</div>
    </div>
</div>

You can instead use:

HTML

<div class="items-list">
    <div class="item">
        <div class="item-name">Product first</div>
        <div class="item-description">Lorem ipsum dolor sit amet, consectetur adipisicing elit.</div>
    </div>
    <div class="item">
        <div class="item-name">Product second</div>
        <div class="item-description">Ratione, ullam, reprehenderit aliquid saepe ab harum.</div>
    </div>
    <div class="item">
        <div class="item-name">Product third</div>
        <div class="item-description"> totam repudiandae velit eum accusantium veritatis.</div>
    </div>
</div>

CSS

.items-list {
    @include make-row();     
    .item 
        @include make-xs-column(12);
        @include make-sm-column(6);
        @include make-md-column(4);
    }
}

---

You can find more examples of Bootstrap mixins in the Sitepoint article - 5 Useful Sass Mixins in Bootstrap.