The word kāraskara means 'a tree'.,
This word is formed from कार + कृ + ट 3.2.21 = कारस्करः ॥ When not meaning a tree, the form is कारकरः ॥ Some do not make this a separate sutra, but include it in the next aphorism.,
कारस्करो वृक्षः
Adhyāya 6 · Pāda 1 · Rule 156