1. being number one trillion in a sequence

1. one of a trillion equal parts of something

Examples

• The trillionth particle was finally detected by the advanced equipment.
• She was the trillionth visitor to the website.
• A trillionth of a second is an incredibly brief moment.
• The measurement was accurate to within a trillionth of a meter.
• Each person represents only a trillionth of the total population.
• The computer processed data in trillionths of a second.