The HTML <wbr> tag is used for specifying a line break opportunity.
The <wbr> tag can be used on very long words or other long strings of text with no spaces. Without the <wbr> tag, these long strings of text could either wrap in strange place (making it difficult to read), or not wrap at all - inadvertently pushing the page layout to the side (again, making it difficult to read and view the document as intended).
<p> The longest word in a major dictionary is: Pneumonoul<wbr>tramicroscopic<wbr>silicovol<wbr>canoconiosis which contains 45 letters </p>
The longest word in a major dictionary is: Pneumonoultramicroscopicsilicovolcanoconiosis which contains 45 letters