a lack, omission, or missing part; absence of something necessary or important
報告書に重要なデータの欠落があった。
There was a missing piece of important data in the report.
設計図の欠落が原因で工事が遅れた。
Construction was delayed because parts of the blueprint were missing.
その説明には論理的な欠落がある。
That explanation has a logical gap/omission.