1. having no physical dimensions; not measurable in terms of length, width, height, or other spatial units
Usage: commonly used in physics and mathematics
2. lacking importance, significance, or substance
Usage: figurative use

Examples

• In physics, a dimensionless quantity is a pure number with no units of measurement.
• The Reynolds number is a dimensionless parameter used in fluid dynamics.
• Ratios and percentages are dimensionless because they represent relationships rather than absolute measurements.
• Her contributions to the project, though dimensionless in scope, were still appreciated by the team.
• The dimensionless analysis helped simplify the complex engineering problem.
• A pure number like π is dimensionless and can be used in any system of units.