1. adding or attaching something to a larger or more important thing
Usage: present participle of annex
2. taking control of a territory and adding it to one’s own country or state
Usage: political/military context

Examples

• The company is annexing the smaller building next door.
• Russia was accused of annexing Crimea in 2014.
• The city council is considering annexing the surrounding suburbs.
• They are annexing additional land to expand the park.
• The empire kept annexing neighboring territories.
• The school is annexing a new wing for science classes.