Some people who like to study at night are called night owls but what do we call a person who likes to study at day time?
1 Answer
A morning person, lark, or early bird is someone who gets up early and is at their best in the morning. These terms are typically considered the opposite of "night owl", in that there are considered to be two types of people, those who are at their best in the mornings and those who prefer nights. Your preference, based on circadian rhythms, is called your chronotype, with at one extreme larks/early birds/morning people and at the other night owls.
Those in between don't have a particular name; they are just average or middling with an intermediate chronotype.
You can see the Wikipedia entries for night owl and lark, and e.g. Merriam Webster synonymns and antonyms: night owl.