A sectional cutoff is the minimum qualifying mark you must score in each individual section of the paper.
In IBPS exams you must clear both the sectional cutoffs and the overall cutoff to qualify.
Sections usually include English, quantitative aptitude and reasoning — each has its own minimum.
Failing even one section means disqualification, no matter how high your total score is.
The exact sectional cutoffs vary every year with the paper’s difficulty and are announced along with the result.