The microscopic scale is the scale of size or length used to describe objects smaller than those that can easily be seen by the naked eye

Naked eye

The naked eye is a figure of speech referring to human visual perception unaided by a magnifying or light-collecting optical device, such as a telescope or microscope. Vision corrected to normal acuity using corrective lenses is considered "naked"...

 and which require a lens

Lens (optics)

A lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. A simple lens consists of a single optical element...

 or microscope

Microscope

A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...

 to see them clearly.

History

By convention it is also used to describe classes of objects which are most commonly too small to see but of which some members are large enough to be observed with the eye. Such groups include the Cladocera

Cladocera

Cladocera is an order of small crustaceans commonly called water fleas. Around 620 species have been recognised so far, with many more undescribed. They are ubiquitous in inland aquatic habitats, but rare in the oceans. Most are long, with a down-turned head, and a carapace covering the apparently...

, planktonic green algae

Algae

Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...

 of which Volvox

Volvox

Volvox is a genus of chlorophytes, a type of green algae. It forms spherical colonies of up to 50,000 cells. They live in a variety of freshwater habitats, and were first reported by Antonie van Leeuwenhoek in 1700. Volvox developed its colonial lifestyle .-Description:Volvox is the most developed...

is readily observable, and the protozoa of which Stentor

Stentor (protozoa)

Stentor, sometimes called trumpet animalcules, are a genus of filter-feeding, heterotrophic ciliate protists, representative of the heterotrichs...

can be easily seen without aid.
The term submicroscopic

Submicroscopic

Submicroscopic is an English adjective used to describe particles of matter that cannot be seen under the most powerful optical microscope available. Atoms are examples of such submicroscopic particles....

 is a similar term used to describe objects that are too small to see with any optical microscope

Optical microscope

The optical microscope, often referred to as the "light microscope", is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. Optical microscopes are the oldest design of microscope and were possibly designed in their present compound form in the...

.

Microscopic is also by association used to classify and describe the units and measurements relevant to very small objects. The antonym

Antonym

In lexical semantics, opposites are words that lie in an inherently incompatible binary relationship as in the opposite pairs male : female, long : short, up : down, and precede : follow. The notion of incompatibility here refers to the fact that one word in an opposite pair entails that it is not...

 to microscopic is macroscopic

Macroscopic

The macroscopic scale is the length scale on which objects or processes are of a size which is measurable and observable by the naked eye.When applied to phenomena and abstract objects, the macroscopic scale describes existence in the world as we perceive it, often in contrast to experiences or...

The units used to describe objects on a microscopic length scale

Length scale

In physics, length scale is a particular length or distance determined with the precision of one order of magnitude. The concept of length scale is particularly important because physical phenomena of different length scales cannot affect each other and are said to decouple...

 are most commonly the Micrometer

Micrometre

A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...

 (µm) - one millionth of 1 metre, and smaller units.

Microscopic is also commonly used as a hyperbole

Hyperbole

Hyperbole is the use of exaggeration as a rhetorical device or figure of speech. It may be used to evoke strong feelings or to create a strong impression, but is not meant to be taken literally....

in the English language to describe small objects of a class that would be expected to be bigger - as in "Her feet are microscopic!"

The prefixe micro stems from the , mikrós, small and σκοπέω, skopéō (look).