White mage's Glare and Holy

[SnowVix]

only english version , in french its mega chatoiement = mega glare . Honestly i don't know why they didn't went for the mega and extra instead of II III bs

Probably because, until FF VIII, all English localizations used numerals to indicate the spell level. Spell suffixes in English FF releases is actually comparatively new.

Its Holyga in Japanese, which directly translates to holy3 using the traditional spell name convention.
This if course circles around to why they skipped Holyra.
-ga typically is for AoE spells, while -ra is typically just more powerful single target, so I presume they used the AoE suffix because holy is an AoE spell and thus is translated unfortunately.

This doesn't follow, in Final Fantasy I, -ra/2 were multi-target, and in the vast majority of single player FFs since 3, ST vs AoE is simply selectable by reducing the damage per target.