Precarious, delicate, risky, sensitive; of uncertain outcome (by analogy with a ship in shallow water).
To touch bottom lightly and without damage, as a vessel in motion.
To perform a touch-and-go landing.
Able to vary or be varied.
Having no fixed quantitative value.
Likely to vary.
Marked by diversity or difference.
Tending to deviate from a normal or recognized type.
A quantity that may assume any one of a set of values.
A shifting wind, or one that varies in force.
A variable star.
A symbol representing a variable.
Something that is variable.
Those parts of the sea where a steady wind is not expected, especially the parts between the trade-wind belts.
Something whose value may be dictated or discovered.
A named memory location in which a program can store intermediate results and from which it can read them.