tree stump; stubble
Refers to the base of a cut tree or plant left in the ground; also used for crop stubble like rice stubble after harvest.
庭の切り株に腰をかけた。
I sat on the tree stump in the garden.
田んぼには稲の切り株が残っている。
Rice stubble remains in the paddy field.
切り株 specifically means the stump left after a tree is cut down, whereas 根っこ can refer to that same stump but also to a living plant's root or an abstract root cause.
Standard kanji spelling; the most common written form.
Variant kanji spelling; less common but still encountered.
Compound of 切り (kiri, 'cutting', from 切る) and 株 (kabu, 'stump, stock'). The reading きりかぶ is a straightforward combination.