Abridgment means transmitting part of an event without every detail. Contradiction arises when two reports concerning the same matter cannot both hold in the relevant respect. Not every omission is a substantive disagreement.
Case 1: One narrator reports that a person supplicated, while another adds that the person raised their hands. The first does not deny that action; the two accounts can coexist.
Case 2: One narrator explicitly denies hand-raising while another affirms it in that same occasion. Now evidence about accuracy and relative transmission strength must be evaluated.
Rule: Always distinguish silence from explicit denial before classifying an additional detail as contradictory.