Refers to tangled, thorny undergrowth or a dense thicket. Often used in literary or descriptive contexts.
If you don't tend it, the garden quickly turns into a tangled thicket of briars.
The mountain path was covered in briars and we couldn't go on.
A thicket is growing thickly in the corner of the garden.
Written with the same kanji 棘, but read とげ it means a single sharp thorn or prickle, while read おどろ it describes a whole tangled thicket of briars.
Rare kanji spelling; the word is usually written in kana.
Standard kana spelling; the word is normally written in kana.
Alternate kanji form; even rarer than 棘.
The origin is uncertain. The kanji 棘 and 荊棘 both mean 'thorn' or 'briar' and are used for their meaning rather than phonetic value.