what does a “core” mean in valorant terms?

for example sen;

did sen 23 and 24 have the same core and this is a new one
or was the 23 sen the different core and the 24/25 one is the new one

ship of theseus type of problem

I would say its your 3 players that has been in the team for the longest time;

23 sen was a shit show but 24 sen would have a core of tenz, zekken and sacy
but 24 sen would have zekken, johnqt, and zellsis

I consider three players who have played together before for at least a year most likely with a coach to be a core.
Examples
Sen Core: Johnqt Zellsis Zekken Kaplan
old Guard Core: Valyn Jonahp Trent Joshrt
Geng Core: Munchkin Karon T3xture Solo

i'il give the example of loud:

22 core: the ones from 22 who remained for 23 (saadhak, less, aspas)
23 core: the ones from 23 who remained for 24 (saadhak, less, cauanzin, tuyz). it also subdivided into 22 core when pancada came back (saadhak, less, pancada)
24 core: the ones from 24 who remained for 25 (cauanzin, tuyz, pancada)

bro when I saw the title I thought of core as in corecore 💀

G2 "core" - Valyn, jonahp, trent. They been on this team since the guard..

as VLR understands a rolling 3 player system where atleast 3 from last roster transition to a new one. It doesn't matter who were the original 5 you started with ,if you always keep 3 and remove the other 2 and repeat.
But obviously we don't see it that way so simply any grp of same 3/4 guys who keep playing together

I personally describe it as when a team retains equal or more than 50% of your roster coming into a season/tournament.

So you have 6 players? 3-4 players that are still active come the next tournament. 7 players? 4-5, and so on.

(It's also how we maintained core connectivity for rosters across different teams/org)