Etymology 1 
From Middle English lowe, lohe, lāh, from Old Norse lāgr (“low”), from Proto-Germanic *lēgaz (“lying, flat, situated near the ground, low”), from Proto-Indo-European *legʰ- (“to lie”). Cognate with Scots laich (“low”), Low German leg (“low, feeble, bad”), Danish lav (“low”), Icelandic lágur (“low”), West Frisian leech (“low”), North Frisian leeg, liig (“low”), Dutch laag (“low”), German läge (“lying, low”). More at lie.
- In a position comparatively close to the ground.
- Small in height.
- Situated below the normal level, or the mean elevation.
- Depressed, sad.
- In an amount nearest to zero, such as low prices; depleted; substandard;
- Of a pitch, suggesting a lower frequency.
- Generally, European men have lower voices than their Indian counterparts.
- Of a loudness, suggesting a lower amplitude.
- They spoke in low voices so I would not hear what they were saying.
- Despicable; lacking dignity; vulgar.
- Now that was low even for you!
- Lacking health or vitality.
- Being near the equator.
- Humble in character or status.
- Simple in complexity or development.
- Designed for the slowest speed, as in low gear.
- Articulated with a wide space between the flat tongue and the palette.
- (in a position comparatively close to the ground): nether, underslung
- (small in height): short, small
- (depressed): blue, depressed, down, miserable, sad, unhappy
- (in an amount nearest to zero, such as low prices): reduced, devalued, low-level
- (of a pitch, suggesting a lower frequency): low-pitched, deep, flat
- (of a loudness, suggesting a lower amplitude): low-toned, soft
- (despicable thing to do): immoral, abject, scummy, scurvy
- (in a position comparatively close to the ground): high
Related terms 
low (plural lows)
- Something that is low; a low point.
- You have achieved a new low in behavior, Frank.
- Economic growth has hit a new low.
- A depressed mood or situation.
- He is in a low right now
- (meteorology) An area of low pressure; a depression.
- The lowest-speed gearing of a power-transmission system, especially of an automotive vehicle.
- Shift out of low before the car gets to eight miles per hour.
- (card games) The lowest trump, usually the deuce; the lowest trump dealt or drawn.
- Close to the ground.
- Of a pitch, at a lower frequency.
- Of a loudness, at a lower amplitude.
- (obsolete, transitive) To depress; to lower.
- (Can we find and add a quotation of Jonathan Swift to this entry?)
Etymology 2 
- obsolete simple past tense of laugh.
Etymology 3 
From Middle English lowen (“to low”), from Old English hlōwan (“to low, bellow, roar”), from Proto-Germanic *hlōanan (“to call, shout”), from Proto-Indo-European *(s)kale-, *klā-, *klē- (“to shout, call”). Cognate with Dutch loeien (“to low”), Middle High German lüejen (“to roar”), Swedish dialectal lumma (“to roar”), Latin calō (“I call”), Ancient Greek καλέω (kaleō), Latin clāmō (“I shout, claim”). More at claim.
Etymology 4 
From Middle English lowe, loghe, from Old Norse logi (“fire, flame, sword”), from Proto-Germanic *lugô (“flame, blaze”), from Proto-Indo-European *leuk- (“light”). Cognate with Icelandic logi (“flame”), Swedish låga (“flame”), Danish lue (“flame”), German Lohe (“blaze, flames”), North Frisian leag (“fire, flame”), Old English līeġ (“fire, flame, lightning”). More at leye, light.
Alternative forms 
low (plural lows)
Etymology 5 
low (plural lows)
- (archaic or obsolete) barrow, mound, tumulus
- A barrow or Low, such as were usually cast up over the bodies of eminent Captains. (Robert Plot, The natural history of Staffordshire, 1686; cited after OED).
- (Scottish dialectal, archaic) a hill
- And some they brought the brown lint-seed, and flung it down from the Low. (Mary Howitt, Ballads and other poems 1847)
From English allow.