late 14c., conservacioun, "preservation of one's health and soundness," from Latin conservationem (nominative conservatio) "a keeping, preserving, conserving," noun of action from past participle stem of conservare (see conserve). Meaning "preservation of existing conditions" in any sense is from mid-15c. Since late 15c., in reference to English municipal authorities who had charge of rivers, sewers, forests, fisheries, etc. Specifically of the environment from 1922.
