Size

Length can be generalized to other linear dimensions (width, height, diameter, perimeter).

In mathematical terms, "size is a concept abstracted from the process of measuring by comparing a longer to a shorter".

Such a magnitude is usually expressed as a numerical value of units on a previously established spatial scale, such as meters or inches.

The perception of size can be distorted by manipulating these cues, for example through the creation of forced perspective.

Visually impaired humans often use echolocation to determine features of their surroundings, such as the size of spaces and objects.

Objects being described by their relative size are often described as being comparatively big and little, or large and small, although "big and little tend to carry affective and evaluative connotations, whereas large and small tend to refer only to the size of a thing".

People who have experienced excessive growth and height significantly above average are described as having gigantism.

The comoving distance – the distance as would be measured at a specific time, including the present – between Earth and the edge of the observable universe is 46 billion light-years (14×10^9 pc), making the diameter of the observable universe about 91 billion light-years (28×10^9 pc).

In poetry, fiction, and other literature, size is occasionally assigned to characteristics that do not have measurable dimensions, such as the metaphorical reference to the size of a person's heart as a shorthand for describing their typical degree of kindness or generosity.

With respect to physical size, the concept of resizing is occasionally presented in fairy tales, fantasy, and science fiction, placing humans in a different context within their natural environment by depicting them as having physically been made exceptionally large or exceptionally small through some fantastic means.

A diagram comparing the size of an average human diver to the size of the modern great white shark , whale shark , and the prehistoric megalodon . The illustration also contains a linear measurement in meters in the middle.
A size comparison illustration comparing the sizes of various planets and stars. In each grouping after the first, the last object from the previous group is presented as the first object of the following group, to present a continuous sense of comparison.
A bat skull next to a ruler used to measure size. Size: 7 mm (0.28 in)
A finch egg next to a dime; a person familiar with the size of a dime would thereby have a sense of the size of the egg.
Forced perspective illusion wherein the perceived size of the Sphinx next to a human is distorted by the incomplete view of both, and the appearance of physical contact between the two.
This animation gives a sense of the scale of some of the known objects in our universe.