The phrase "on time" refers to something that occurs at the expected or scheduled moment. It implies punctuality and adherence to a set timeline, suggesting that an event or action takes place precisely when it is supposed to, without delay.
The phrase "on time" combines the preposition "on," meaning in a state of being or in accordance with, and the noun "time," which originated from the Old English "tima," referring to a period or interval. This form has evolved over centuries, aligning with the modern understanding of punctuality.