nostalgia (n.) Look up nostalgia at Dictionary.com
1770, "severe homesickness" (considered as a disease), Modern Latin (French nostalgie is from 1802), coined 1668 by Johannes Hofer, as a rendering of German heimweh, from Greek algos "pain, grief, distress" (see -algia) + nostos "homecoming," from PIE *nes- "to return safely home" (cognate with Old Norse nest "food for a journey," Sanskrit nasate "approaches, joins," German genesen "to recover," Gothic ganisan "to heal," Old English genesen "to recover"). Transferred sense (the main modern one) of "wistful yearning for the past" first recorded 1920.