オツ, イツ, おと, きのと
the latter, duplicate, strange, witty, fishhook radical (no. 5)
JLPT1 G7 S1 F1841
A representation of vapors rising (compare 气) and hitting a blocking element such as a ceiling, or the top of a container. *Second in a series* and *second calendar sign* are borrowed meanings. 乙 appears in dual-element characters such as 軋, 亂 and 札 in the form 乚.
[Full Kanji Etymology List]