- A thought that occurs later, often as a realization or correction.
- A consideration or action that is added later, often as an after effect.
From after ("following") + thought ("a mental process").
- The dessert was an afterthought, added to the menu at the last minute.
- He realized, as an afterthought, that he had forgotten to lock the door.
- He made the comment as an afterthought, not thinking it would cause offense.
- Safety was an afterthought during the construction of the building.
- She had an afterthought, and decided to bring an umbrella before leaving the house.