Liquid, a.
Etymology: [L. liquidus, fr. liquere to be fluid or liquid; cf. Skr. ri to ooze, drop, li to melt.]
1. Flowing freely like water; fluid; not solid. Yes, though he go upon the plane and liquid water which will receive no step. Tyndale.
2. (Physics)
Being in such a state that the component parts move among themselves, but do not tend to separate from each other as the particles of gases and vapors do; neither solid nor aëriform; as, liquid mercury, in distinction from mercury solidified or in a state of vapor.
3. Flowing or sounding smoothly or without abrupt transitions or harsh tones. "Liquid melody." Crashaw.
3 more senses
4. Pronounced without any jar or harshness; smooth; as, l and r are liquid letters.
5. Fluid and transparent; as, the liquid air.
6. Clear; definite in terms or amount.[Obs.] "Though the debt should be entirely liquid." Ayliffe. Liquid glass. See Soluble glass, under Glass.
1 other Webster entry under this spelling
Liquid, n.
1. A substance whose parts change their relative position on the slightest pressure, and therefore retain no definite form; any substance in the state of liquidity; a fluid that is not aëriform.
Note: Liquid and fluid are terms often used synonymously, but fluid has the broader signification. All liquids are fluids, but many fluids, as air and the gases, are not liquids.
2. (Phon.)
A letter which has a smooth, flowing sound, or which flows smoothly after a mute; as, l and r, in bla, bra. M and n also are called liquids. Liquid measure, a measure, or system of measuring, for liquids, by the gallon, quart, pint, gill, etc.
Shades of meaning
Fernald has no entry of its own for liquid; he lists it under fluid.
Where he writes about it:
A fluid is a substance that, like air or water, yields to any force that tends to change its form; a liquid is a body in that state in which the particles move freely among themselves, but remain in one mass, keeping the same volume, but taking always the form of the containing vessel; a liquid is an inelastic fluid; a gas is an elastic fluid that tends to expand to the utmost limits of the containing space. — from fluid
All liquids are fluids, but not all fluids are liquids; air and all the gases are fluids, but they are not liquids under ordinary circumstances, tho capable of being reduced to a liquid form by special means, as by cold and pressure. — from fluid
Water at the ordinary temperature is at once a fluid and a liquid. — from fluid