으로(eu-ro, euro)
Particle indicating direction, means, cause, attached after nouns with a final consonant.
When to use
Direction (consonant ending), Means or method, Cause or reason (consonant ending)
The nuance
Used after nouns ending with a consonant. Exception: after ㄹ final consonant, use '로'.
로(ro)
Particle indicating direction, means, cause, attached after nouns without a final consonant or with ㄹ final consonant.
When to use
Direction (no consonant ending), Means or method, Cause or reason (no consonant ending)
The nuance
Used after nouns ending without a consonant or with ㄹ consonant.