Impedances

noun

1. The act of impeding; that which impedes; a hindrance.
2. A measure of the opposition to the flow of an alternating current in a circuit; the aggregation of its resistance, and inductive and capacitive reactances; the ratio of voltage to current treated as complex quantities.
3. A quantity analogous to electrical impedance in some other energy domain
4. (by analogy, usually with “mismatch”) a measure of the opposition caused by differences between two paradigms, especially between object-oriented development and relational databases