Remembering the function of HTML5 <figcaption> tag is easy because the name is suggestive of its use. The HTML5 <figcaption> tag is mainly utilized along with the <figure> element. It is the key in adding proper caption.
The HTML5 <figcaption> tag is a new function in HTML5 so this is not present in HTML4.01.
Using the HTML5 <figcaption> tag is not a problem because this also supports the Event Attributes and Global Attributes in HTML5. All the major web browsers also work perfectly with it such as Internet Explorer, Firefox, Google Chrome, Safari and Opera.