This is the 54th most frequent Korean word.
원
"원" can mean "circle," "won" (Korean currency), or "institution," depending on context.
In this sentence, '원' is used as a unit of South Korean currency.
책 값은 백 원입니다.
The price of the book is 100 won.
Here, '원' is part of '원칙', which means principle, indicating a fundamental rule or concept.
이 프로그램은 좋은 원칙에 따라 설계되었습니다.
This program was designed following good principles.
In this case, '원' is part of '학원', which means an academy, commonly a private educational institute.