Meaning

• The act of impeding; that which impedes; a hindrance.

• 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.

• A quantity analogous to electrical impedance in some other energy domain

• (by analogy, usually with “mismatch”) a measure of the opposition caused by differences between two paradigms, especially between object-oriented development and relational databases