Yes, you are correct! The ending "-ide" is usually used to indicate a negative ion. In the case of the nitride ion, it means that the ion has a charge of -3. So, N3- is called the nitride ion.
To name a compound that contains the nitride ion, you would typically use the name of the metal or positive ion followed by the name of the negative ion with the "-ide" ending. For example, in the compound Mg3N2, the metal ion is magnesium (Mg) and the negative ion is nitride (N), so the compound is named magnesium nitride.
I hope this explanation helps! Let me know if you have any other questions.