What is the meaning of -으로?

to, toward: directional case marker, in a physical sense

into, direction of a change: directional case marker in a metaphorical sense; expresses transformation or direction towards a certain time

using, out of; with: instrumental case marker, marking material, instruments, or means of doing something

due to; from: instrumental case marker, marking causation

as; as being; in the state of: instrumental case marker, marking state, manner, status, or capacity

as of: instrumental case marker, marking an update in a list of previous events

from; egressive case marker, in a physical or chronological sense

Marks the direct object for certain action verbs, especially verbs that have a direct impact on the object.

Used in various expressions:

1. See -으로 하여 (-euro hayeo, “because of; via”).
2. See -으로 하여금 (-euro hayeogeum, expresses the agent in a causative construction).
3. See -으로 더불어 (-euro deobureo, “together with”).

See -으로 하여 (-euro hayeo, “because of; via”).

See -으로 하여금 (-euro hayeogeum, expresses the agent in a causative construction).

See -으로 더불어 (-euro deobureo, “together with”).

Source: wiktionary.org