Concrete

#d2d1cd

A neutral that has no useful hue — it reads as a grey. It is very light — it works as a page background, not as text.

Hex

#d2d1cd

RGB

210, 209, 205

OKLCh

86.0% 0.006 95.1°

CIELAB (D50)

83.8, -0.2, 2.1

What is true of this colour, and of no other

43 other named colours sit within ΔE00 2 of it — this part of the space is crowded, and the names here are finer distinctions than most people make.
It uses almost none of the chroma available here: this is a grey with a trace of hue rather than a colour.
As text on white it measures APCA Lc 24.5; on black, Lc -78.6. The sign is the polarity, which the WCAG ratio discards.
Built into an eleven-step scale, 10 of the 10 adjacent pairs stay ΔE00 2 apart — see the ramp.
All three dichromacies see it as very nearly the same colour you do: its hue is not the part carrying its identity.

Text on this colour

White text

1.53:1 — fails AA

Black text

13.74:1 — passes AA

Black text is the better of the two at13.74:1. That is enough for body text.

As text on white, it needs to change

#787773 is the nearest colour of the same hue that passes AA on white, at 4.50:1. Only the lightness moved.

Try it against your own background

The same colour, with one cone missing

As you see it

#d2d1cd

protanopia

#d1d1cd · ΔE00 0.5

deuteranopia

#d1d1cd · ΔE00 0.6

tritanopia

#d1d1ca · ΔE00 1.9

Run a whole palette through all three

The twelve nearest named colours

Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isThundersnow at ΔE00 0.497: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.

ThundersnowΔE00 0.497 · #d2d1ce
Gazebo GreyΔE00 0.549 · #d1d0cb
HalationΔE00 0.674 · #d1d1ce
Light BleachesΔE00 0.71 · #d5d4d0
Touch of GreyΔE00 0.793 · #d1cfca
Seashell GreyΔE00 0.845 · #d5d4cf
Guild GreyΔE00 0.961 · #d2d1cb
Pewter VaseΔE00 1.013 · #cececb
White MetalΔE00 1.061 · #d1d1cf
Light BrumeΔE00 1.082 · #d6d5d2
Slow PerchΔE00 1.172 · #d5d4ce
On the RocksΔE00 1.235 · #d0cec8

12 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.