粘性

• Reading: ねんせい
• Romaji: nensei
• Kanji breakdown: 粘 (nen/neba-) — sticky, viscous; 性 (sei/shō) — nature, property
• Pronunciation: /ne.ɴ.se.i/

Meaning

Viscosity; the property of a fluid that resists flow due to internal friction between its molecules; also used figuratively to mean stickiness or tenacity.

A noun used in fluid dynamics and rheology. 動粘性 (kinematic viscosity) and 絶対粘性 (dynamic viscosity) are measured in fluid mechanics. High-viscosity fluids like honey and tar flow slowly; low-viscosity fluids like water and air flow easily. Temperature strongly affects viscosity: most liquids become less viscous when heated. In medicine, blood viscosity is clinically significant.

Examples

1. 蜂蜜は水に比べて粘性が非常に高く、ゆっくりとしか流れない。 Honey has a much higher viscosity than water and flows only very slowly.
2. 温度が上昇するとエンジンオイルの粘性が低下するため、適切なグレード選択が重要だ。 As temperature rises, the viscosity of engine oil decreases, so selecting the appropriate grade is important.
3. 血液の粘性が高い状態が続くと血栓が形成されやすくなり、心筋梗塞のリスクが高まる。 A prolonged state of high blood viscosity makes blood clots more likely to form, increasing the risk of heart attack.

Usage Guide

Context: fluid dynamics, engineering, medicine, materials science

Tone: neutral

Origin & History

Compound of 粘 (nen — sticky, viscous) and 性 (sei — nature, property). Together they describe the inherent sticky or resistant quality of a substance.

Cultural Context

Era: Modern

Generation: Students and professionals

Social background: Technical