What is the infinitive form of a verb?

The infinitive is the unconjugated form of the verb. So, this is what we look for in the dictionary when we're looking for a verb. Infinitives end with either -ir, -er, or -ar. Some verbs are very regular when we talk about their conjugations. Let's take 'comer'. To say 'I eat', we say 'comO' - this verb is conjugated, but to say 'to eat', we use 'comER'. You can see that we have taken its root 'com' and added '-er' instead of '-o'. 'Comer' does not mention who or what is eating, nor does it say when. It is just the simplest form of the verb. Some verbs are not so regular and their conjugations don't resemble their roots at all. For example the infinitive of 'to go' is 'ir', but to say 'I go', is 'voy'. But for the most part infinitives are fairly easy to form.