This minimalist example will not wrap DIV2 into a second line. Both DIV1 and DIV2 will stay on the same line:

<div style="white-space: nowrap;"> 
    <div style="display: inline-block;"> DIV1 </div>
    <div style="display: inline-block;"> DIV2 </div>
</div>

Here is an output:

DIV1 DIV2

Here are the requirements:
-1- your container DIV should have white-space: nowrap;
-2- each of your cell DIV(s) should have display: inline-block;

Why this is important? – When you need to modify existing HTML, but you only have access to CSS.

RE:
– prevent DIV from wrapping to next line
– 2017-09-20 WE 10:33