A part
弟
Shown as a part of 2 words so far, read 2 ways.
で 1 word
- 弟子でしpupil, disciple, apprentice
弟子 · here “younger brother”
だい 1 word
- 兄弟きょうだいsiblings (humble), brothers and sisters
兄弟 · here “younger brother”
Also written with 弟
These words contain the character in their spelling but show no breakdown that names it, so nothing is claimed about its role in them.