least vs low

In the smallest or lowest degree; in a degree below all others. 

Used for forming superlatives of adjectives, especially those that do not form the superlative by adding -est. 

Something of the smallest possible extent; an indivisible unit. 

The most little; the smallest amount or quantity of something. 

In a low mean condition; humbly; meanly. 

In a time approaching our own. 

In a path near the equator, so that the declination is small, or near the horizon, so that the altitude is small; said of the heavenly bodies with reference to the diurnal revolution. 

Close to the ground. 

With a low voice or sound; not loudly; gently. 

Under the usual price; at a moderate price; cheaply. 

Of a pitch, at a lower frequency. 

Lacking health or vitality, strength or vivacity; feeble; weak. 

Situated close to, or even below, the ground or another normal reference plane; not high or lofty. 

Being a nadir, a bottom. 

Not high in status, esteem, or rank, dignity, or quality. (Compare vulgar.) 

Depleted, or nearing deletion; lacking in supply. 

Disparaging; assigning little value or excellence. 

Dead. (Compare lay low.) 

Having a small or comparatively smaller concentration of (a substance, which is often but not always linked by "in" when predicative). 

Below the batter's knees. 

Humble, meek, not haughty. 

Low-cut. 

Grave in pitch, due to being produced by relatively slow vibrations (wave oscillations); flat. 

Depressed in mood, dejected, sad. 

Favoring simplicity (see e.g. low church, Low Tory). 

Being near the equator. 

Quiet; soft; not loud. 

Pertaining to (or, especially of a language: spoken in) in an area which is at a lesser elevation, closer to sea level (especially near the sea), than other regions. 

Of less than normal height or upward extent or growth, or of greater than normal depth or recession; below the average or normal level from which elevation is measured. 

Made with a relatively large opening between the tongue and the palate; made with (part of) the tongue positioned low in the mouth, relative to the palate. 

Small, not high (in amount or quantity, value, force, energy, etc). 

Simple in complexity or development. 

Lesser in value than other cards, denominations, suits, etc. 

Designed for a slow (or the slowest) speed. 

An area of low pressure; a depression. 

The minimum atmospheric temperature recorded at a particular location, especially during one 24-hour period. 

A cheap, cost-efficient, or advantageous price. 

A period of depression; a depressed mood or situation. 

A flame; fire; blaze. 

A low point or position, literally (as, a depth) or or figuratively (as, a nadir, a time when things are at their worst, least, minimum, etc). 

The lowest trump, usually the deuce; the lowest trump dealt or drawn. 

The lowest-speed gearing of a power-transmission system, especially of an automotive vehicle. 

Barrow, mound, tumulus.