<DFN> </DFN>

DFN tells when a term is used for the first time. Text inside DFN is italicized, and it lets users know that this is the first time that term is used.

For example:

<DFN>HEY!</DFN> That was the first time I used HEY! In this site.
HEY! That was the first time I used HEY! In this site.