It's a demonstrative pronoun phrase that highlights a distinction between masculine, feminine, and neuter genders in Latin.
* Hic refers to masculine things.
* Haec refers to feminine things.
* Hoc refers to neuter things.
This is similar to the English "this" which doesn't change based on the gender of the noun it refers to.
For example:
* Hic liber - This book (masculine)
* Haec penna - This pen (feminine)
* Hoc tabula - This table (neuter)