n. 粗砂岩

[ noun ]
a hard coarse-grained siliceous sandstone
<noun.substance>

Gritrock \Grit"rock`\ (gr[i^]t"r[o^]k`), Gritstone \Grit"stone`\
(-st[=o]n`)n. (Geol.)
See {Grit}, n., 4.

Grit \Grit\, n. [OE, greet, greot, sand, gravel, AS. gre['o]t
grit, sant, dust; akin to OS griott, OFries. gret gravel,
OHG. grioz, G. griess, Icel. grj[=o]t, and to E. groats,
grout. See {Groats}, {Grout}, and cf. {Grail} gravel.]
1. Sand or gravel; rough, hard particles.

2. The coarse part of meal.

3. pl. Grain, esp. oats or wheat, hulled and coarsely ground;
in high milling, fragments of cracked wheat smaller than
groats.

4. (Geol.) A hard, coarse-grained siliceous sandstone; as,
millstone grit; -- called also {gritrock} and {gritstone.}
The name is also applied to a finer sharp-grained
sandstone; as, grindstone grit.

5. Structure, as adapted to grind or sharpen; as, a hone of
good grit.

6. Firmness of mind; invincible spirit; unyielding courage;
fortitude. --C. Reade. --E. P. Whipple.