It had been in the game since 2.0, but during 2.0 there weren't as many jobs, so only one job or another would get left out of a full party with all different things.
Come the addition of Ninja, groups started to shun weaker jobs like DRG even more heavily than they had in the past, since there was more choice.
Come 3.0 a true, "Meta" developed after a few tweaks to the Heavensward jobs, resulting in the mathematically highest DPS composition being a WAR, DRK, NIN, DRG, MCH, BRD, AST, and SCH. This was due to WAR bringing slashing debuff, increasing its, the DRK's, and the NIN's DPS. The NIN brought Trick Attack increasing everyone's DPS. The MCH brought Hypercharge, same thing as Trick Attack back then. BRD brought Battle Voice and Foe's Requiem, increasing the Healer's DPS as well as NIN's Ninjutsu damage. DRG brought Disembowl, originally the piercing debuff, increasing its damage as well as BRD's, along with Battle Litany, which was originally a group wide +20% crit rate. SCH brought Selene who originally increased Spell Speed/Skill Speed for the whole party, providing a very small increase to overall raid DPS, allowing everyone to fit one more GCD into burst windows. AST brought Spread Balance, increasing everyone's DPS. DRK brought higher DPS than PLD, and it allowed the comp to shun MNK, since original Delirium did the same INT down, reducing magical raidwides, that Dragon Kick used to do.
Combining these jobs allowed for exceedingly powerful burst windows, allowing fights to be cleared far more quickly than any other composition. It carried on into 4.0, largely unchanged except PLD > DRK(and WAR too, but slashing debuff) now, until they buffed SMN's Devotion buff, causing it to actually replace MCH in the comp a patch or so after they added UCoB iirc.
This was what lead to all content creators for XIV talking about, "The Meta" for the better part of 2016/2017, and that discussion didn't die down until one of the World First groups beat UCoB with a DRK in the comp instead of a WAR. Note that the rest of that meta group was unchanged, merely resulting in infinitesimally lower DPS for the NIN, while everyone else in the party's DPS remained largely at meta levels. However, public perception swayed to, "Meta doesn't matter, see!" so the Devs moved towards making meta comp less pivotal.
A meta comp will always still exist given inherent imbalance for rotational design differences, but it's less important now than ever before.