what's in a name?

Garnet was a very popular name mostly in 1900-1930-ish but since then, the use of Garnet the name has decreased drastically. Since Final Fantasy IX is set back in the 'old fashioned days', using the name Garnet makes perfect sense.

Nowadays, in today's modern era, a person named Garnet is automatically assumed to be female, however, when the name was at its peak usage, most people named Garnet were actually men (or perhaps this is the case today too, but as far as I know, Garnet is primarily a female name these days). Garnet is an English name, and it comes from a surname that meant "hinge" in Old English. It was originally used as a nickname for people who sold hinges, although I have no idea how or why. Garnet also has Latin origin and means 'red seed'. Garnet also references to our princess being wealthy and royal, since Garnet is a precious, expensive gemstone. Garnet is the birthstone for January, the month in which Garnet was born in. Garnet means a lot of things and whether it be hinges or seeds, it all somehow revolves around the color red.

nicknames

Being a princess with a mysterious past, it's not surprising that a super secret real name will spring up, as well as aliases to hide from the crowds. Garnet held the nickname Dagger for a time, which she took on after Zidane tells her she'll need an alias in order to freely roam the continent, despite Steiner's rebuttal that the princess need not sneak around like a common thief. Garnet noticed Zidane's dagger, asked what it was, and upon receiving the answer, Garnet decided her nickname shall be that. A dagger is a short sword, a knife really, that thieves commonly use back in such old fashioned days.

The name Dagger is the way Zidane and friends have come to know Garnet, and it is her link to them just as it is their link to her. Her friends are commoners compared to her royal highness and this name keeps them on common ground, rather than placing Princess Garnet high up on a pedestal. Zidane doesn't even refer to the princess as Garnet anymore, because it's too much acknowledgement about the extreme difference in their status in society. Garnet really likes this nickname.

and the secret one?

Garnet is not the princess' true name, however, just as the Queen is not her real mother. Her real name is Sarah, which has its roots in the Hebrew language. Sarah means princess or lady and I think that is pretty self explanatory. The name Sarah is in reference to the original Final Fantasy princess, Sara without an 'h'.