Meaning

noun accuracy with which an electronic system reproduces the sound or image of its input signal

noun the quality of being faithful

origin15th century, from Middle English [Term?], from Middle French fidélité, from Latin fidēlitās, from fidēlis (“faithful”), from fidēs (“faith, loyalty”) (English faith), from Proto-Indo-European *bʰidʰ-, zero-grade of *bʰeydʰ- (“to command, to persuade, to trust”) (English bide). Doublet of fealty.

Etymology from Wiktionary, CC BY-SA 3.0