The expression confession is not defined in the Evidence Act. A confession is a statement which either admits the offence or at any rate,substantially all the facts which constitute the offence.
Admissions and confessions are exceptions to hearsay rule.The Evidence Act places them in the category of relevant evidence,presumably on the ground that as they are declarations against the interest of the person making them,they are probably true.
Evidentiary value of confession is not very great.
Confessions and admissions must either be accepted as a whole or rejected as a whole and the court is not competent to accept only inculpatory part while rejecting exculpatory part as incredible.