A BSc is a first university degree in a science subject. The letters stand for Bachelor of Science. You earn it after about three or four years in things like biology, chemistry, physics, maths, or computer science. You say it as three letters, B-S-C, not as one word. In Britain, Ireland, Taiwan and many other places, BSc is the usual spelling. In the United States people often write BS for the same kind of degree. A BA is the sister degree on the arts and humanities side. Though actually, universities do not all draw the line in the same place: some put psychology or economics under a BSc, some under a BA.