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📕 rednote ID(小红书号)：3881567312

Perimeter Definition, Usage, and Examples (2 meaning)

Meaning 1：outer boundary (perimeter)

perimeter 🔊

/pəˈrɪmɪtər/

The total length of the outer line of a shape, like the distance around a playground.

outer boundary 🔊

➕

/ˈaʊtər ˈbaʊndəri/

The continuous line forming the boundary of a closed geometric figure or an area; its total length.

📁 Category：Buildings & Places 🔖 Level：初级

📘 Details & Usage

📖 Root Explanation

From Greek 'peri-' (around) + 'metron' (measure).

💡 Mnemonic

Imagine a PERI-meter is the distance you walk AROUND (peri-) to MEASURE (meter) a fence.

📖 Example

The students ran around the perimeter of the school field during sports day. 🔊 The students ran along the outer boundary of the school field during the athletic event.

🔗 Collocations

calculate the perimeter – to determine the total length of the outer boundary

measure the perimeter – to find the length around the outside

perimeter of a rectangle – the total distance around a rectangular shape

🔄 Synonyms

circumference (n.) – The enclosing boundary of a circle or other curved geometric figure.

border (n.) – The edge or boundary of something, often a surface.

edge (n.) – The outside limit of an object, area, or surface.

🚫 Antonyms

interior (n.) – The inner part or inside of something.

center (n.) – The middle point of a circle or sphere, equidistant from every point on the circumference or surface.

🌱 Derivatives

perimetric (adj.) – Relating to or situated around the perimeter.

📖 Cultural Story

The word entered English in the early 15th century via Latin 'perimetros', from Greek, primarily used as a geometrical term. It was adopted into military and security contexts in the 20th century to describe defensive boundaries.

Meaning 2：outermost edge (perimeter)

perimeter 🔊

/pəˈrɪmɪtər/

The outermost area or edge of a place, like the area just inside the fence of a property.

Perimeter example of a secured outer edge with a fence and camera.

outermost edge 🔊

➕

/ˈaʊtərməʊst ɛdʒ/

The outer limits or boundary of an area, especially one that is guarded or monitored.

📁 Category：Buildings & Places 🔖 Level：中级

📘 Details & Usage

📖 Example

Security cameras were installed along the perimeter of the campus to monitor all entrances. 🔊 Surveillance devices were placed around the outer boundary of the university grounds to watch all access points.

🔗 Collocations

secure the perimeter – to make the outer boundary safe from intrusion

patrol the perimeter – to walk or travel around the outer edge of an area for surveillance

outer perimeter – the furthest or most external boundary line

🔄 Synonyms

boundary (n.) – A line that marks the limits of an area; a dividing line.

periphery (n.) – The outer limits or edge of an area or object.

fringe (n.) – The outer, marginal, or extreme part of an area, group, or sphere of activity.

🚫 Antonyms

core (n.) – The central or most important part of something.

heart (n.) – The central or innermost part of something.