Flow resistance

Medicine

 * Vascular resistance

Physics

 * Electrical resistance, the measure of the degree to which a conductor opposes the flow of an electric current through that conductor
 * Friction
 * Drag (physics) ("air resistance"), fluid or gas forces opposing motion and flow
 * The inverse of Hydraulic conductivity, the ease with which water can flow through pore spaces or fractures in soil or rock
 * Thermal resistance, a measure of difficulty of heat flow through a substance
 * Thermal conductivity, how well heat flows through a substance
 * Thermal resistance in electronics, heat considerations in electronics design

Music

 * Resistance to airflow through a wind instrument due to air friction (for instance, a tightly-coiled French horn has higher resistance than a straight unvalved slide trumpet)