The preterite is a grammar name for a past verb form — the one that places an action or a state back in the past, as finished then. In English, this is what schoolbooks usually call the past simple: walked, ate, was, went. Though actually, English teachers in Taiwan almost never say preterite to students. They say past tense or 過去式. Preterite is a more technical word, borrowed from older European grammar (Latin and French schoolbooks). You will meet it in linguistics, in careful grammar writing, and in descriptions of other languages — Spanish, German, French — where the preterite is a specific past form, different from other past forms like the imperfect. In English the picture is messier than the tidy label. Walked is a preterite. Have walked is not: that is the present perfect, a different past-ish form. Was walking is the past continuous. So preterite does not mean “any past.” It means the simple past form. You may also see the spelling preterit, mostly in American writing. Same word. It is a classroom and textbook word, not a word for the street. Nobody says “I used the preterite” at dinner, unless they teach grammar.

過去式（文法／語言學用語，多指簡單過去式；台灣課堂通常只說「過去式」，較少用這個詞本身）