Pronunciation: [lˈɛnz] (IPA) 
The correct spelling of the word is "lens". This is pronounced as /lɛnz/ in IPA phonetic transcription. It refers to a curved piece of glass or plastic that is used in various optical devices, such as cameras and eyeglasses. The confusion of spelling may arise from the similar-sounding "lense," which is considered a misspelling. To avoid confusion, remember to keep in mind that "lens" is spelled with just one "e" in the middle.
A lens, commonly spelled as "lens" but also interchangeably written as "lense," is a transparent optical component that refracts, or bends, light, converging or diverging it to form an image. It is usually made of glass or plastic with a curved surface, although some lenses can be made from other materials. A lens possesses two surfaces: one convex, meaning it curves outward, and one concave, meaning it curves inward. These curved surfaces interact with light to control its direction, enabling the formation, enlargement, or distortion of images.
Lenses are extensively used in various fields, particularly in optics and photography. They are an integral component in optical instruments such as cameras, telescopes, microscopes, and binoculars. The ability of lenses to focus light allows these instruments to capture and magnify images, making them indispensable in the field of visual observation and documentation.
Lenses are classified into two main categories: converging lenses and diverging lenses. Converging lenses, also known as convex lenses, curve outwards and bring parallel rays of light to a focal point, resulting in the formation of real and inverted images. On the other hand, diverging lenses, also called concave lenses, curve inwards and cause parallel rays of light to spread out, creating a virtual and upright image.
In summation, a lens, or "lense," refers to a transparent optical device with curved surfaces that manipulates the direction of light, resulting in the formation of images. It is widely employed in optical systems and photography, playing a crucial role in capturing, magnifying, and observing objects across various fields of study.
The word "lense" is a variant spelling of "lens". The etymology of the word "lens" can be traced back to the Latin word "lens", which means "lentil", referring to a type of legume. This Latin term was then adopted into Old English as "lens" in the sense of a "lens-shaped object". Over time, the spelling evolved to "len[s]se" in Middle English and eventually settled on the modern spelling "lens". The use of "lense" as an alternative spelling emerged through a process known as analogical leveling, where the final 's' was added to match the plural form of the word. However, "lens" without the final 's' remains the dominant and accepted spelling.
