Stream
An informal grouping of subjects: Science, Commerce, Humanities (Arts) and vocational.
CBSE does not officially have streams. Schools group subjects into Science, Commerce and Humanities blocks for timetable reasons, and colleges often describe eligibility in stream terms. In the current scheme of studies you can mix subjects across streams if your school can timetable the combination.
When a college says "science stream", it usually means a specific set of subjects (for example Physics, Chemistry and Mathematics) rather than the label on your report card. Always check the subject list, not the stream name.