Disappointingly the English infinitive is nothing to do with flying to the far reaches of outer space. It's a grammatical term used to describe the use of the 'to' form of a verb. For a more comprehensive explanation, with examples, watch our English infinitive video lesson online.If you are researching English grammar because you are learning English as a second language, ESO can help. With an ESO subscription you can watch more pre-recorded grammar videos online, whenever you have the spare time, to help you learn the basics underpinning the English language. We can also help you prepare for internationally-recognised qualifications with intensive courses, and practise English online with our qualified English teachers, in one-to-one lessons.