A tussock is a small, thick clump of grass that grows up on its own, higher and denser than the grass around it, so the ground looks bumpy rather than smooth and flat. You meet the word where the land is rough and wet — moorland, marshes, hillsides, the New Zealand high country, where whole landscapes are called 'tussock country'. It is a countable noun. Walkers know tussocks as an ankle problem: you step between them and turn your foot. You will also see it used before another noun — 'tussock grass', 'tussock moor' — for the kind of grass that grows this way. It is a fairly specialised word: common in nature writing, hiking talk and farming, but not something that comes up in a normal city day.

草叢、叢生的草墩（一簇一簇高起來的那種草）。台灣講草地多半是平整的一片，這個字強調的是「一叢一叢、走路會絆到」的樣子。