is "sido" an irregular or regular word?

Question

Because when you take er off ser, you get s. And then you add the ending. So what makes it irregular?

Answer 1

Irregular or irregular verbs just refers to whether the verb conjugation follows a recognizable pattern for verbs of their conjugation class.

So while Ser is considered an irregular, 2nd conjugation verb in conjugating a lot of tenses (in all moods) it is regular in forming its past participle. For 2nd conjugation ER verbs the normal pattern is to remove the ER ending and add ido. Ser follows that pattern. Likewise, it would be regular considering its gerundio. S+iendo (just like other regular ER verbs).

In the same vein, you could consider it a regular verb when forming the conditional tense, the future tense, the pluperfect, preterite perfect, present perfect, imperfect subjunctive, past perfect subjunctive, and all of its progressive tense, etc. because all of those tenses follow the same patterns as other ER verbs.

Answer 2

"Sido" is regular word for Participle. I have checked in verbix site. I use "ser" for verb conjugation in spanish. I noticed black which is regular word. If it is red, it is irregular.