reserve (v.) Look up reserve at Dictionary.com
mid-14c., from Old French reserver, from Latin reservare "keep back, save back," from re- "back" + servare "to keep, save, preserve, protect" (see observe). Reserved (in manner) first recorded 1601 in Shakespeare ("All's Well" v.3).
reserve (n.) Look up reserve at Dictionary.com
"something stored up," 1650s, from reserve (v.).