Etymology
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buoy (n.)
"float fixed in a place to indicate the position of objects underwater or to mark a channel," late 13c., boie, probably from Old French buie or Middle Dutch boeye, both of which likely are from Proto-Germanic *baukna- "beacon, signal" (see beacon). OED and Century Dictionary, however, suggest it is from Middle Dutch boeie or Old French boie "fetter, chain" (see boy), "because of its being fettered to a spot."
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buoy (v.)
1590s, "to mark with a buoy," from buoy (n.). Meaning "keep something from sinking, keep afloat" is from 1650s, probably from the noun in the extended sense of "buoyant object thrown from a vessel to assist someone in the water stay afloat." It is attested earlier (1640s) in the figurative sense (of hopes, spirits, etc.). Related: Buoyed; buoying.
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buoyant (adj.)
1570s, perhaps from Spanish boyante, present participle of boyar "to float," from boya "buoy," from Dutch boei (see buoy (n.)). Of personalities, etc., from c. 1748. Related: Buoyantly.
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*bha- (1)

*bhā-, Proto-Indo-European root meaning "to shine."

It forms all or part of: aphotic; bandolier; banner; banneret; beacon; beckon; buoy; diaphanous; emphasis; epiphany; fantasia; fantasy; hierophant; pant (v.); -phane; phanero-; phantasm; phantasmagoria; phantom; phase; phene; phenetic; pheno-; phenology; phenomenon; phenyl; photic; photo-; photocopy; photogenic; photograph; photon; photosynthesis; phosphorus; phaeton; sycophant; theophany; tiffany; tryptophan.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit bhati "shines, glitters;" Greek phainein "bring to light, make appear," phantazein "make visible, display;" Old Irish ban "white, light, ray of light."

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