CSS Language Speak: Container vs Wrapper?

According to this answer:

In programming languages the word container is generally used for structures that can contain more than one element.

A wrapper instead is something that wraps around a single object to provide more functionalities and interfaces to it.

This definition matches with meaning of words and it's useful for HTML structures like:

<ul class="items-container">
    <li class="item-wrapper">
        <div class="item">...</div>
    </li>
    <li class="item-wrapper">
        <div class="item">...</div>
    </li>
    <li class="item-wrapper">
        <div class="item">...</div>
    </li>
    <li class="item-wrapper">
        <div class="item">...</div>
    </li>
    <li class="item-wrapper">
        <div class="item">...</div>
    </li>
</ul>

There is no difference between them.

It's just what you like to call the <div> that, often, contains all content of a page