Picosecond (ps)
Definition: Picosecond na one trillionth of one second.
History/origin: Picoseconds come make sense as electronics, laser physics, and signal processing begin work for very short time scale.
Current use: People dey use picoseconds for ultrafast optics, semiconductor timing, telecoms, and scientific measurements of very fast events.
Day (day)
Definition: Day na normal calendar time unit based on Earth rotation. For converters, dem dey treat 1 day as 24 hours or 86,400 seconds.
History/origin: Long before mechanical clocks, people track time with sunrise, sunset, and the repeating light–dark cycle wey later become the civil day.
Current use: Days dey used for due dates, delivery windows, travel plans, medication intervals, streaks, reservations, payroll periods, and calendar-based scheduling.