1. A unit of time equal to one quintillionth of a second (10⁻¹⁸ seconds); used in physics and chemistry to measure extremely brief events at the atomic and subatomic scale.
Usage: technical; scientific

Examples

• Researchers used attosecond pulses to observe electron behavior in atoms.
• The laser produces light bursts lasting only a few attoseconds.
• Attosecond spectroscopy allows scientists to study ultrafast chemical reactions.
• An attosecond is to a second what a second is to about 31.7 billion years.
• The development of attosecond technology earned the 2023 Nobel Prize in Physics.