# invasion

/ˌɪnˈveɪʒən/ (US) · /ɪnvˈeɪʒən/ (UK)

Source: https://englishreference.com/word/invasion
Updated: 2026-06-19

## Senses

### 1. military attack

noun · CEFR B2

when an army enters another country by force to take control of it.

For teachers: the act of an armed force entering a foreign territory with the intent of conquest or regime change.

- The country prepared its defenses after hearing news of a possible invasion.
- Historians still debate whether the massive naval invasion could have been avoided through more rigorous diplomatic efforts in the preceding months.

### 2. unwanted entry

noun · CEFR B2

when people or things enter a place where they are not wanted or disturb your private life.

For teachers: an unwelcome or intrusive entry into a place or a person's private affairs.

- The constant phone calls felt like an invasion of her privacy.
- The celebrity described the paparazzi's presence at the private funeral as a cruel invasion of a family's grief.

### 3. medical/biological spread

noun · CEFR C1 · Technical

the spread of a disease, bacteria, or cancer cells inside the body.

For teachers: the spreading of pathogenic microorganisms or malignant cells into healthy tissue or throughout an organism.

- Doctors were worried about the invasion of cancer cells into the nearby organs.
- The pathology report confirmed the invasion of the tumor into the lymphatic system, necessitating a more aggressive course of chemotherapy.

Usage: Often used to describe the aggressive movement of cancer cells into surrounding tissues.

### 4. surgical entry

noun · CEFR C1 · Technical

the act of cutting into the skin or entering the body during a medical procedure.

For teachers: the breaching of the skin barrier or entry into a body cavity during a clinical or surgical procedure.

- Modern surgery aims to limit the invasion of the body to help patients heal faster.
- The surgeon opted for a laparoscopic approach to minimize tissue invasion and reduce the risk of post-operative infection.

Usage: Commonly found in the phrase 'minimally invasive' to describe surgery with small cuts.

## Examples

- The country prepared for a possible invasion by its neighbor.
- The sudden invasion of tourists during the summer months often overwhelms the small island's infrastructure.
- Historians debate whether the military invasion was a strategic necessity or a catastrophic overreach that destabilized the entire region for decades to come.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.