...and other semantics.
We seem to have our own vocabulary among name-nerds. When the average person comes on a forum, asking for a "unique" name, they're likely to get suggestions like Anaïs, Acacia, or Avalon....but what they probably want is something along the lines of Annalise, Aviana, or Ashlyn. It can be quite frustrating to those of us obsessives when someone claims to want to avoid trendy names, but then asks if Kaedin or Brantley is the better option. ("How can they be trendy? They're not popular at all!")
I'd love to find a way to uniformly standardize vocabulary in all naming forums, but I'll have to settle for preaching to the choir. :p
So, here's my take on common naming terms:
Popular--Top 10-20 or so on the spelling-adjusted charts. Ex: Jacob, Emily, Aiden, Madison
Common--Top 100ish. Ex: Alexis, Gabriel, Colton, Brianna
Uncommon--Top 100-500. Ex: Malachi, Jude, Eleanor, Fiona
Very uncommon--Top 500-1000. Ex: Dashiell, Susana, Deacon, Selah
Unique/Rare--Below 1000. Ex: Tobin, Ramsay, Cordelia, Priya
Trendy--suddenly spiking in use, or having characteristics that have quickly become more common. Ex: Jayden, Ava, Mackenzie, Keegan
Classic--maintaining a relatively stable level of usage (regardless of popularity). Ex: William, August, Elizabeth, Nina.
Outdated--a name that was once classic/trendy, but has fallen out of common usage. Ex. Amanda, Ronald, Gary, Barbara
Vintage--a formerly outdated name that is coming back into usage. Ex: Hazel, Stella, Theo, Asa.
Traditional: a name that has been in use for at least several generations. Ex: Michael, Mary, Sophia, Ethan
Modern: a name relatively new in usage, whether through gender-switch, cultural borrowing, invention, or some other means. Ex: Avery (for girls), Teagan (surname), Mia (cultural borrowing), Cambria (place name).
IMHO, a name can be both traditional and trendy (Olivia, Isabella), or modern and classic (Ashley, Brooke, Ryan). A name could also be unique but trendy (Maxson, Breelyn), or unique but traditional (Coral, Josephina, Otto).
*disclaimer--I did previously write this up on a certain forum, so if it seems vaguely familiar; that's why. ;)