을

1. 조 See Object Marker.

Follows words that end with consonants.

See 를, ㄹ for words that end with vowels.

2. 어미 See ㄹ, 을 (관형사형 전성 어미)

Follows a 용언 (verb) that ends in a consonant. See ㄹ for 용언 (verb) that ends in a vowel.

3. (乙) 명 The second

a. Indicates the second in a series.

b. The second 십간

c. Abbreviation of 을방

d. Abbreviation of 을시

e. When there's more than one of something, the name of one of them.