buoy (v.) Look up buoy at Dictionary.com
late 16c., "to mark with a buoy," from buoy (n.). Meaning "rise up, lift, sustain" is from c. 1600, perhaps influenced by Spanish boyar "to float," ultimately from the same source. In the figurative sense (of hopes, spirits, etc.) it is recorded from 1640s. Related: Buoyed; buoying.
buoy (n.) Look up buoy at Dictionary.com
late 13c., perhaps from either Old French buie or Middle Dutch boeye, both from Proto-Germanic *baukna- "beacon, signal" (see beacon). OED, however, suggests it is from Middle Dutch boeie or Old French boie "fetter, chain" (see boy), "because of its being fettered to a spot."