1) Of a liquid 2) Supported 
floating on the surface
The material remaining above the pellet after centrifugation of a suspension. 
• (n.) The liquid remaining after solids suspended in the liquid have been sedimented by gravity or by centrifugation. Contrasted with the solid sediment, or (in centrifugation) the pellet. • (a.) Swimming above; floating on the surface; as, oil supernatant on water.
The soluble liquid &action of a sample after centrifugation or precipitation of insoluble solids.
<chemistry> The soluble liquid fraction of a sample after centrifugation or precipitation of insoluble solids. ... (19 Jan 1998) ... 
(soo″pәr-na´tәnt) the liquid lying above a layer of precipitated insoluble material.
Su`per·na'tant adjective [ Latin supernatanus , present participle of supernatare to swim above; super above + natare to swim.] Swimming above; floating on the surface; as, oil supernatant on water. 
Type: Term Pronunciation: sū′pĕr-nā′tănt See: supernatant fluid
[adj] - (chemistry) of a liquid 2. [n] - a liquid lying above a sediment (floating on the surface)
supernatant 1. Swimming above, floating on the surface (as a lighter liquid on a heavier one). 2. A reference to that part of a floating body that is above the surface. Word families with similar applications about: 'swim, swimming': necto-; neusto; pleo-.
adjective of a liquid; floating on the surface above a sediment or precipitate; `the supernatant fat was skimmed off`
floating above or on the surface.