- Noun. (physics) A measure of the opposition to the flow of an alternating current in a circuit; the aggregation of its resistance, inductive and capacitive reactance. Represented by the symbol Z.
- Noun. (physics, usually with “mechanical”) a measure of opposition to motion of something subjected to a force.
- Noun. (physics, usually with “acoustic” or “sound”) the sound pressure divided by the particle velocity and the surface area through which an acoustic wave propagates.
- Noun. (context, by analogy) a measure of the opposition caused by differences between two paradigms, especially between object oriented development and relational databases.