There are three conjugations (groups) of French verbs:
1st group ending in the infinitive in -er: parler, glisser.
2nd group has the ending -ir in the infinitive: finir, bénir .
3rd group: These include irregular verbs, ending in -oir, -re, also some in -ir. Moreover, the verb aller (to go), envoyer, renvoyer belongs here. Verbs in -ir belonging to the 3rd group (also these verbes with prefixes like abstenir, retenir) : tenir, venir, partir, sentir, mentir, vêtir, dormir, servir, courir, mourir, fuir, gésir, repentir , ouvrir, couvrir, offrir, souffrir, cueillir, saillir (tressaillir), bouillir, faillir, verbs in -quérir.